Imaging prevention method and system

ABSTRACT

As an imaging prevention method for interfering unauthorized imaging of visual image projected on a screen, there is employed a method for projecting infrared light to a viewer/audience direction from at least one or more infrared light projector means disposed at a rear side of the screen. According to the method, an amount of the infrared light directly is incident into an imaging apparatus whereby increasing the prevention effect since the more infrared light is directly incident into the imaging apparatus of a person conducting the unauthorized act.

RELATED APPLICATION DATA

[0001] This application claims priority to provisional application No.60/291,414, and the disclosure of that application is incorporatedherein by reference to the extent permitted by law.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to technology for interferingunauthorized copy of visual images shown on a screen of a visual imagesystem.

[0004] 2. Description of the Related Art

[0005] Following technique is disclosed as means to interfere such anunauthorized copy. The technique has been developed to utilizedifference between visual characteristic of human eyes and imagecharacteristic of imaging apparatus such as cameras, and employsinfrared light to realize means to interfering the unauthorized copy.More specifically, infrared light is projected onto a screen surfacefrom an infrared light projector disposed at a vicinity of an visualimage projector or other remote position so as that infrared lightreflected on the screen surface can be incident into the imagingapparatus of a person conducting the unauthorized act of copying thevisual image appearing on the screen. In other words, an infrared lightvisual image, which is irrelevant to the main feature of visual images,is inevitably recorded on the visual image that is obtained in theunauthorized manner. Accordingly, overall quality of visual imagesrecorded through the unauthorized manner are degraded. Sometime, such adegraded visual image enables to determine a location where theunauthorized act is taken place. Of course, viewer/audiences would notbe affected by the interfering means and can enjoy the featurepresentation of visual images appeared on the screen since infraredlight can not be recognized by human eyes.

SUMMARY OF THE INVENTION

[0006] However, a reflection ratio of infrared light in a conventionalcinema screen is not high enough. Accordingly, it is difficult tomaterialize desirable effect in a conventional system described abovebecause of the low reflection ratio in the cinema screen as well aslengthy infrared light path between the screen and the infrared lightprojector disposed at the vicinity of the visual image projector.Further, there is a technical problem of that relatively high outputpower is required for the infrared projector so as to provide anysignificant effects on the visual images that are illegally recorded.

[0007] The present invention addresses the above-mentioned problems.

[0008] It would be desirable to provide a practical technique capable ofproducing equal or more effective prevention effect than theconventional one while using an infrared light projector apparatus of alower power.

[0009] According to the present invention, following means are provided.

[0010] (A) As a first means, the following technique is provided. In thetechnique, infrared light is projected to a viewer/audience directionfrom one or more infrared light projector means disposed at a screenside whereby enabling the infrared light to be incident into imagingmeans of a person conducting the unauthorized act. In embodiments of thepresent invention, the infrared light projector means may be realized invarious configurations that include an infrared light projectorapparatus, an infrared light projector, an infrared light emitting diodeor any other device/apparatus/system capable of projecting infraredlight. Furthermore, in embodiment of the present invention, the imagingmeans may be a camera, camcorder, video recorder or any otherdevice/system comprising an image sensor capable of obtaining imagedata. The technique will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. That is,ample intensity of the infrared light may be radiated into the imagingmeans even when the low power infrared light projector apparatus isused.

[0011] (B) As a second means, another technique is provided. In theanother technique, infrared light is actively reflected by an infraredlight reflection means so as that the reflected infrared light may beincident into imaging means of a person conducting the unauthorized act.In embodiments of the present invention, the infrared light reflectionmeans may be an infrared light mirror or any otherdevice/apparatus/member capable of reflecting infrared light. Thetechnique also will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. That is,ample intensity of the infrared light may be incident into the imagingmeans even when the low power infrared light projector apparatus isused.

[0012] (C) As a third means, still another technique is provided. In thestill another technique, infrared light is intermittently emittedinstead of continuous emission. Various advantages are realized by theintermittent emission. For example, a location in which the visual imagepiracy was taken place may be identified in case that the infrared lightintermittent emission is outputted in accordance with a predeterminedinformation. Alternatively, an emission intensity of infrared light maybe frequently changed whereby enabling to degrade quality of visualimages illegally recorded so much as that viewing of visual imagesrecorded in the unauthorized manner becomes impossible due to the rapidchange of intensity level.

[0013] (D) As a fourth means, still another technique is provided. Inthe still another technique, infrared light is selectively projectedonto an area or areas of the screen surface, in which brightness islower (for example, area or time period having a brightness of thescreen surface equal or less than a predetermined value). The techniqueallows to emit or increase an amount of infrared light in a part wherean amount of the visual image light is low whereby enabling to increaserelative effects of the infrared light. Accordingly, more effectiveprevention of the visual image piracy may be possible. Further, in casethat certain information is superposed on the infrared light, suchinformation is surely recorded on the visual images illegally recorded.

[0014] (E) As a fifth means, still another technique is provided. In thestill another technique, infrared light is projected from a plurality ofinfrared light projector means disposed in the vicinity of a screenwhereby having the reflected infrared light be incident into imagingmeans of a person conducting the unauthorized act. The technique usesthe similar principle as that of the conventional technique except theinfrared light projector apparatus in the present embodiment areselectively disposed in the vicinity of the screen. Accordingly, thereflected infrared light may be significantly increased whereby enablingto promote the prevention effect further.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The other objects, features and advantages of the presentinvention will become more apparent from the following description ofthe presently preferred exemplary embodiments of the invention taken inconjunction with the accompanying drawings, in which:

[0016]FIG. 1 is a schematic diagram illustrating one embodiment (part 1)wherein infrared light is projected to a viewer/audience direction froma rear side of a screen;

[0017]FIG. 2 is a schematic diagram illustrating a theater screen;

[0018]FIG. 3 is a schematic diagram illustrating one embodiment (part 2)wherein infrared light is projected to a viewer/audience direction froma rear side of a screen;

[0019]FIG. 4 is a schematic diagram illustrating one embodiment whereininfrared light is projected to a viewer/audience direction from a frontside of a screen;

[0020]FIG. 5 is a schematic diagram illustrating one embodiment (part 1)wherein infrared light is projected to a viewer/audience direction froma vicinity of a screen;

[0021]FIG. 6 is a schematic diagram illustrating one embodiment (part 2)wherein infrared light is projected to a viewer/audience direction froma vicinity of a screen;

[0022]FIG. 7 is a schematic diagram illustrating one embodiment whereinreflection means of high reflection ratio for infrared light isemployed;

[0023]FIG. 8 is a schematic diagram illustrating an example of actuatorapparatus for the reflection means of high reflection ratio;

[0024]FIG. 9 is a schematic diagram illustrating one embodiment whereininfrared light is emitted intermittently;

[0025]FIG. 10 is a schematic diagram illustrating an example of emissionpattern (part 1) for a case in which infrared light is emittedintermittently;

[0026]FIG. 11 is a schematic diagram illustrating an example of emissionpattern (part 2) for a case in which infrared light is emittedintermittently;

[0027]FIG. 12 is a schematic diagram illustrating an example of emissionpattern (part 3) for a case in which infrared light is emittedintermittently;

[0028]FIG. 13 is a schematic diagram illustrating an example of emissionpattern (part 4) for a case in which infrared light is emittedintermittently;

[0029]FIG. 14 is a schematic diagram illustrating an example of emissionpattern (part 5) for a case in which infrared light is emittedintermittently;

[0030]FIG. 15 is a schematic diagram illustrating one embodiment(part 1) wherein infrared light is selectively projected onto scene orarea in the screen of low brightness;

[0031]FIG. 16 is a schematic diagram illustrating an example of aninfrared light projector apparatus having a unit configuration;

[0032]FIG. 17 is a schematic diagram illustrating an example ofconfiguration of a film projector apparatus;

[0033]FIG. 18 is a schematic diagram illustrating relationship betweenshutter operation and projection operation of infrared light;

[0034]FIG. 19 is a schematic diagram illustrating an example of shuttersensor arrangement;

[0035]FIG. 20 is a schematic diagram illustrating an example of emissioncontrol for an infrared light projector apparatus having a unitconfiguration;

[0036]FIG. 21 is a schematic diagram illustrating one embodiment (part2) wherein infrared light is selectively projected onto scene or area inthe screen of low brightness;

[0037]FIG. 22 is a schematic diagram illustrating one embodiment whereininfrared light from a vicinity of a screen; and

[0038]FIG. 23 is a schematic diagram illustrating an example ofconfiguration of an infrared light projector apparatus attached with anprojection directing actuator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] (A) Conceptual Embodiment

[0040] First, conceptual embodiments of a imaging prevention method andsystem in accordance with the present invention will now be described.

[0041] (1) As a method for interfering unauthorized imaging of visualimages projected onto a screen, the following is provided. The methodcomprises the steps of: disposing at least one or more infrared lightprojector means at a rear side of the screen or the other side of thescreen from the viewer/audiences; and projecting infrared light from theat least one or more infrared light projector means to a viewer/audiencedirection whereby enabling the infrared light to enter an imaging meansof a person conducting the unauthorized act.

[0042] The method will eliminate needs of reflecting infrared light at ascreen surface of poor reflection ratio. Accordingly, the projectedinfrared light may be effectively incident into the imaging means of aperson conducting the visual image piracy. Further, ample intensity ofthe infrared light may be radiated into the imaging means even when thelow power infrared light projector means is used.

[0043] Various methods for projecting infrared light may becontemplated. For example, the various methods may include a method forprojecting infrared light by letting at least a part of the infraredlight pass through space besides the screen, a method for projectinginfrared light by transmitting at least a part of the infrared lightthrough the screen, or a method for projecting infrared light by lettingat least a part of the infrared light pass through a pass-through partdisposed in the screen.

[0044] Here, remarkably high prevention effect is expected for the firstexample or the third example since there is no factor of drasticallyreducing an amount of light in cases where the infrared light isdirectly incident into the imaging means.

[0045] Further, the first example include such a case in which theinfrared light is reflected by an object other than the screen. Theobject may have a high reflection ratio for the infrared light and maybe, for example, a wall or an infrared light reflection mirror so calleda hot mirror. Alternatively, the object that reflects the infrared lightmay be one that scatters the infrared light. In the following, theobject is the same as ones reflecting the infrared light.

[0046] As the pass-through part in the third example, a constructionsuch as a cut or gap extending to one direction (e.g. slit), a hole partthrough the screen (e.g. small hole or bore), or any other constructionin which the infrared light may pass through the screen from the rearside to the front side may be contemplated. Here, it is preferred tohave one or more pass-through parts in the screen. In general, strongerinfrared light is output toward the front side of the screen as morenumber of the pass-through parts are provided. Further, the pass-throughparts may be distributed uniformly on a whole screen area orconcentrated in a particular area (e.g. screen center part or screenperipheral part).

[0047] On the other hand, significant prevention effect is expected forcase, like the second example, where the infrared light passed throughthe screen may be incident into the imaging means for some screenconstruction types. Particularly, sufficient prevention effect isexpected for a type in which an original visual image is projected frombehind the screen since it is expected high transmission ratio of theinfrared light is also high.

[0048] For the second example, followings may be used. The means includea screen having an area of transmitting the infrared light with athinner member part compared to the other part of the screen (forexample, a concaved part) thereby enabling easily transmission of theinfrared light, a method for varying a member which easily transmits theinfrared light and letting the infrared light pass the member, or ascreen comprising members that easily pass the infrared light.

[0049] In any of the above-described examples, a projection direction ofvisual image onto the screen may be either a direction from theviewer/audience side to the screen or a direction from the rear side ofthe screen viewing from the viewer/audience to the screen side(viewer/audience direction). The same applies to the following othermethods.

[0050] (2) As one of methods for interfering unauthorized imaging ofvisual image projected on a screen, the following technique is provided.In the technique, infrared light is projected to a viewer/audiencedirection from one or more infrared light projector means disposed at afront side of the screen viewing from the viewer/audience side wherebyenabling the infrared light to be incident into imaging means of aperson conducting the unauthorized act.

[0051] The method will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. Further, moreample amount of the infrared light may be incident into the imagingmeans compared to that of the previous method since there is almost nointerfering object exist in between the infrared light projector meansand the imaging means as well as the infrared light may be projectedfrom close vicinity of a person conducting the unauthorized act.

[0052] A projection direction of the infrared light projector means maybe fixed or varied automatically. The projection direction, that may bevariably set, may include a particular direction (not only singledirection but also a plurality of directions) or any arbitrarydirection. By varying the projection direction, it becomes possible toeliminate space that could allow the unauthorized imaging act. The sameapplies to the other methods.

[0053] Further, when the infrared light projector means and the infraredlight reflection means are used in combination, the infrared light maybe projected to a wider area similar to the previous case describedabove in case that at least one of means is capable of varying theprojection direction or the reflection direction. Further, this methoddoes not exclude use of an object having a high infrared lightreflection ratio, such as a wall or infrared light reflection mirror.

[0054] (3) As a method for interfering unauthorized imaging of visualimage projected on a screen, the following is provided. In the method,infrared light is directly projected to a viewer/audience direction fromone or more infrared light projector means disposed in a vicinity of thescreen whereby enabling the infrared light to be incident into imagingmeans of a person conducting the unauthorized act.

[0055] The method also will eliminate needs of reflecting infrared lightprojected onto a screen surface of poor reflection ratio. Accordingly,the projected infrared light may be effectively incident into theimaging means of a person conducting the unauthorized act. Further, inthis method, more ample amount of the infrared light may be incidentinto the imaging means compared to the method of (1) since there isalmost no interfering object exist in between the infrared lightprojector means and the imaging means as well as the infrared light maybe projected from close vicinity of a person conducting the unauthorizedact.

[0056] Here, in the vicinity of the screen, not only space along outerperiphery of the screen but also space extending outward from the outerperiphery are included. Further, space in the vicinity of the screen isnot necessary to be the same plane of the screen in strict sense. It issupposed that the vicinity of the screen may be positioned at a frontside or back of a hypothetical plane including the screen with having acertain amount of distance in between.

[0057] (4) As a method for interfering unauthorized imaging of visualimage projected on a screen, the following is provided. In the method,infrared light, that is projected from at least one or more infraredlight projector means, is reflected to a viewer/audience directionwhereby enabling the infrared light to be incident into imaging means ofa person conducting the unauthorized act.

[0058] The method does not use a screen surface of poor reflection ratioas the reflection means. Instead, it uses the infrared light reflectionmeans with the high reflection ratio whereby enabling more ample amountof the infrared light to be incident into the imaging means of a personconducting the unauthorized act. Accordingly, it becomes possible torealize lowering of output of the infrared light projector means.

[0059] Here, the infrared light reflection means may be disposed in anyarbitrary position. For example, it may be disposed in a front side ofthe screen viewing from the viewer/audience side, or in a rear side ofthe screen, or in the vicinity of the screen. In any case, it is desiredthat the position may be one from which ample amount of the infraredlight incident into the imaging means of a person conducting theunauthorized act.

[0060] Further, the infrared light reflection means or its reflectionsurface may be configured as that its reflection direction is variedarbitrary by actuator means. By utilizing such infrared light reflectionmeans, an area, in which the infrared light prevention is possible, maybe expanded compared to that of the fixed reflection direction.

[0061] Further, the infrared light reflection means may be, for example,an infrared light reflection mirror. Such member may be in a film formor any other predetermined forms with arbitrary thickness.

[0062] (5) As a method for interfering unauthorized imaging of visualimage projected on a screen, the following is provided. In the method,an infrared light is intermittently emitted from at least one or moreinfrared light projector means whereby enabling predeterminedintermittent emission pattern to be recorded on imaging means of aperson conducting the unauthorized act.

[0063] The method enables to record the intermittent emission patternirrelevant to the present feature of program on visual images recordedin the unauthorized manner by intermittently emitting the infraredlight. Recorded pattern of the intermittent light differs depending onin what form the infrared light incident into the imaging means.

[0064] For example, in case in which scattered light of the infraredlight which light flux is uniformly spread out is incident, an emissionintensity of infrared light may be frequently changed whereby enablingto degrade quality of visual images so much as that viewing becomesdifficult. Further, for another example, in case in which spread oflight flux is limited to a certain size (including pin point size), anintensity of infrared light may be frequently changed at a part of thescreen. This case similarly enables to degrade quality of visual imagesso much as that viewing becomes difficult.

[0065] Further, it is obvious that this emission control method may becombined with the above described methods (1)-(4). That is, the infraredlight projector means may be disposed at any arbitrary location.

[0066] It is also possible to combine this method with the method inwhich the infrared light reflection means actively reflect.Alternatively, following methods may be possible for controlling theinfrared light emission.

[0067] (5a) Method for controlling at least one or more infrared lightprojector means based on predetermined code information to emitintermittently so as to record information along time axis direction:

[0068] This method superimposes information on the emission timingitself. That is, prescribe information (for example, output date/time,output location, screen number (number uniquely identifiable of eachscreen), output apparatus, a person performing output, and any otherinformation required to identify a location where the unauthorized actis conducted) is forced to be recorded as point image pattern in binaryform. Of course, it is also possible to prevent the viewing by theintermittent emission itself.

[0069] When a plurality of the infrared light projector means are used,all of them may be turned on/off at the same time, or emitting positionmay be changed in sequence in relay form like (5b) while the emissiontiming itself may be controlled as the same way as a case in which onlysingle infrared light projector means is used. Further, the emittingposition may be randomly changed or changed in sequence in accordancewith a predetermined rule when the plurality of the infrared lightprojector means are used.

[0070] (5b) Method for controlling plural infrared light projector meansbased on predetermined code information to emit intermittently in relayform so as to record information along time axis direction:

[0071] Although this method may be applicable to a case in which theemission timing itself compose meaning like in the case of (5a) (nomeaning in a position of the light image), the method enables tosuperimpose desired information in light image positions themselves tobe recorded. For example, a following method may be applicable. In themethod, the light image position may be changed in accordance with aseries of binary data representing the desired information when twolight image positions are provided wherein “1” of the binary data isassigned to one of the positions and “0” of the binary data is assignedto the other. Of course, it is also possible to prevent the viewing bythe intermittent emission itself. Further, the desired information maybe forced to be recorded without affecting the viewing of theviewer/audience (only an effect comparable to natural noise will berecognized by many of the viewer/audiences) when area size of therecorded light image is small.

[0072] (5c) Method for controlling plural infrared light projector meansbased on predetermined code information to emit intermittently in relayform so as to record two-dimensional information:

[0073] In this method, positions at which the light images appeared arecompressed along the time axis direction to compose single plane so asto reveal the recording of a two dimensional information (figure, codeor any other recognizable shape). For example, the method may definecorrespondences between the light image position itself and theinformation by dividing the screen into four sections and by assigningone theater a pattern in which the light image appears on all of thefour sections and another theater another pattern in which the lightimage appears on three sections except the upper right section. Further,it is also possible to vary two dimensional information on a transitiontrajectory of the light image positions. For example, it is possible toconfigure so as that a two dimensional information may be appeared whenthe light image is traced as it appeared. Alternatively, it is alsopossible to superimpose the information in the light image transitiondirection itself.

[0074] (5d) Method for controlling plural infrared light projector meansto emit in predetermined combination so as to record two-dimensionalinformation:

[0075] The method enables to instantly identify the light imagesdispersed in the time axis direction as in (5c) on the same screen. Forexample, it is possible to associate the plural light images with a barcode pattern. Alternatively, more information may be recorded byassociating patterns (graphical pattern) representative of the lightimages with multi-valued code information and changing the displayingpattern along the time axis direction. This method is a composite methodfor combining information along the time axis and information in twodimensional direction.

[0076] (5e) Method for disposing at least one or more infrared lightprojector means comprising an array of light emitting devices at a rearside of the screen viewing from a viewer/audience side, and controllingindividual light emitting device to generate an emission pattern of theinfrared light whereby enabling a predetermined information to berecorded in imaging means of a person conducting the unauthorized act:

[0077] This method is similar to embodiment (5d) except the infraredlight projector means comprises plural light emitting devices and thedisposing location of the infrared light projector means is at behindthe screen. Information may be displayed on the same screen in ainstantly recognizable form even by controlling the emission by eachlight emitting device. Of course, more information may be recorded byassociating patterns (graphical pattern) representative of the lightimages with multi-valued code information and changing the displayingpattern along the time axis direction. Alternatively, the method may beconfigured so as that predetermined information is displayed byutilizing only the emission of plural light emitting devices arrayed inthe same infrared light projector means or the predetermined informationis displayed by utilizing the emissions of combined light emittingdevices, each set of the devices being arrayed in different infraredlight projector means.

[0078] (6) As a method for interfering unauthorized imaging of visualimage projected on a screen, the following is provided. In the method,brightness at a screen surface is detected by at least one or more lightsensors facing the screen surface and being disposed behind the screenviewing from viewer/audience side, and an amount of infrared lightprojected from an infrared light projector means is increased as thedetected brightness of the screen surface decrease.

[0079] This method is a method for increasing the amount of the infraredlight projected onto a scene or area of the screen surface having thelow brightness. By using this method, the amount of the infrared lightis lowered when the brightness of the screen surface is high (screen isbright) and thus prevention effect of the infrared light is small, andthe amount of the infrared light is increased when the brightness of thescreen surface is low (screen is dark) and thus prevention effect of theinfrared light is large. Accordingly, the prevention effect is highercompared to a case in which the same amount of the infrared light isconstantly emitted or the infrared light is projected uniformly over awhole screen surface.

[0080] The infrared light projector means may be disposed in anarbitrary position. Further, as regarding which path the infrared lightshould follow to enter the imaging means of a person conducting theunauthorized act, the path requiring reflection on the screen, the pathfor direct incident through space other than the screen, or the pathpassing through or transmitting through the screen is possible. Ofcourse, it is possible to combine this method with the above describedmethods (1)-(6a) Method for detecting brightness at a screen surfacewith at least one or more light sensors that are disposed behind thescreen viewing from viewer/audience side and facing the screen surface,and projecting infrared light from at least one or more infrared lightprojector means when the detected brightness of the screen surface isequal or less than a predetermined brightness whereby enabling theinfrared light to be incident into an imaging means of a personconducting an unauthorized act:

[0081] This method enables to increase the relative brightness level ofthe infrared light with respect to the visual image of the main featureprogram, and to effectively amplify the effect of the infrared lightsince the infrared light is projected onto the screen surface during thedark scene or the dark period. Accordingly, the ample effect may begenerated with the infrared light projector means with a low outputpower. Also in this case, the infrared light projector means may bedisposed any arbitrary position. It is possible to contemplate that aroute of the infrared light to be incident into the imaging means of aperson conducting the unauthorized act may be one requiring reflectionat the screen, one passing through space other than the screen to directincident, one passing or transmitting through the screen, or the like.Of course, it is possible to combine this method with the above-citedmethods (1)-(5).

[0082] Further, it is possible to select the vicinity of screen centeras a portion in which brightness of the screen is to be determined. Alight image of the infrared light may be visualized more clearly byemitting the infrared light when the brightness at the vicinity ofscreen center is low. Accuracy of determination of whether the visualimage is dark or bright may increase in case that a plurality of thedetection results are used and the infrared light is projected when apredetermined number of the detection results, in which brightness ofthe screen surface is detected to be equal or less than a predeterminedbrightness, are detected, so as to promote reliability. Alternatively,an average value of the plural detection results may be set as thebrightness of the screen surface and compared with a threshold value.

[0083] Here, “the predetermined brightness”, that is the threshold valuefor determining the screen brightness, may be fixed independent of thevisual images projected on the screen or varied to be a different valuedepending on the visual image. Alternatively, the predeterminedbrightness may be independently adjusted by a manager side in acommercial system such as a movie theater. In this case, a functiondisabling an adjustment to a value equal or less than a predeterminedbrightness may be employed as a safety measure whereby enabling tocountermeasure an ill-intentioned manager. Alternatively, thepredetermined brightness may be controlled in accordance with aninstruction from a content-provider side connected via a network. Ofcourse, such instruction may also be notified off-line.

[0084] Further, “the predetermined number”, that is the threshold valuefor determining whether the infrared light should be projected or not,may include a number “one”. In general, the accuracy of determinationincreases as the threshold value for determination increases. Thepredetermined number may also be independently adjusted by a managerside in a commercial system such as a movie theater. In this case, theinfrared light is constantly emitted when no detection result isinputted (case of NO SIGNAL) as well as a function disabling anadjustment to a value more than the number of detection results to beused for the determination may be employed as a safety measure wherebyenabling to countermeasure an ill-intentioned manager. Furthermore, thepredetermined value may also be controlled in accordance with aninstruction from a content-provider side connected via a network. Ofcourse, such instruction may also be notified off-line.

[0085] Here, the emission of the infrared light may be an emission thatgenerates a light image to-be-recorded extending to a whole area of thescreen or a light image extending only to a portion or multiple portionsof the screen. The following methods may be contemplated as a method forcontrolling the emission of the infrared light.

[0086] (6b) Method for detecting brightness at a screen surface with atleast one or more light sensors facing the screen, and individuallyprojecting infrared light from at least one or more infrared lightprojector means in case that the brightness of the screen surface isequal or less than a predetermined brightness whereby enabling theinfrared light to be incident into imaging means of a person conductingan unauthorized act, wherein the at least one or more light sensors aredisposed behind the screen viewing from a viewer/audience side, and theinfrared light projector means projecting the infrared light isassociated with an area corresponding to the light sensor detecting thebrightness equal or less than the predetermined brightness:

[0087] This method enables to adaptively project the infrared light ontopartial area(s) of the screen surface, in which the brightness is low,whereby enabling the recording of light images of the infrared light atcorresponding partial area(s). With utilizing the method, it would bedifficult to view the visual images recorded in the unauthorized waysince the infrared light is recorded onto the partial area with the lowbrightness. Of course, it is possible to combine this method with theabove-cited methods (1)-(5).

[0088] (6c) Method for reproducing time information, in which brightnessat a screen becomes equal or less than a predetermined brightness value,from a recording medium, and projecting infrared light from at least oneor more infrared light projector means in accordance with the reproducedinformation whereby enabling the infrared light to be incident into animaging means of a person conducting an unauthorized act:

[0089] This method is not to control the infrared light emission inreal-time based on the detection results of actual measurements, but amethod for controlling the infrared light emission based on theinformation provided from a distributor of the main feature program or aprovider or the like. That is, the method obtains the information ofmethod (6) from the recording medium and requires no light sensor or thelike.

[0090] The recording medium to be read may be ones recording informationrequired for the emission control of the infrared light distributed fromthe distributor or the provider to the projector side as well as onesused for recording information received by the projector side via anetwork. Of course, it is possible to combine this method with theabove-cited methods (1)-(5).

[0091] (6d) Method for reproducing area and time information, in whichbrightness at a screen becomes equal or less than a predeterminedbrightness value, from a recoding medium, and individually projectinginfrared light from at least one or more infrared light projector meansassociated with corresponding areas on the screen in accordance with thereproduced information whereby enabling the infrared light to beincident into an imaging means of a person conducting an unauthorizedact:

[0092] This method does not control the infrared light emission based onthe real-time detection results. Instead, the method is a method forcontrolling the infrared light emission based on the informationprovided from the distributor of the main feature program or theprovider or the like. With employing such method, it is also possible toattain an object of enabling the record of the infrared light image atthe partial areas by adaptively projecting the infrared light to thescreen surface at the partial areas having the low brightness. Ofcourse, it is possible to combine this method with the above-citedmethods (1)-(5).

[0093] (6e) Method for receiving information from a network for time inwhich brightness at a screen becomes equal or less than a predeterminedbrightness value in synchronization with a projection of visual images,and individually projecting infrared light from at least one or moreinfrared light projector means in accordance with the receivedinformation whereby enabling the infrared light to be incident into animaging means of a person conducting an unauthorized act:

[0094] This method is a method for acquiring information relating tomethod (6) via the network and controlling the infrared light emission.With employing such method, it is also possible to attain an object ofenabling the record of the infrared light image at the time periods byadaptively projecting the infrared light to the screen surface at thetime periods having the low brightness. The information may be receivedin synchronization with the output of visual images when the projectionof the main feature program to the screen is performed only once. Whenthe output of the main feature program is repeated plural times, thepredetermined information (information indicating time periods in whichbrightness of the screen becomes equal to or less than the predeterminedbrightness value) may be received every time the output is performed.Alternatively, it is also possible to acquire the predeterminedinformation in real-time for the first time and use the informationrecorded when it was received for the first time for the subsequentoutputs. Of course, it is also possible to combine this method with theabove-cited methods (1)-(5).

[0095] (6f) Method for receiving information from a network for area andtime in which brightness at a screen becomes equal or less than apredetermined brightness value in synchronization with a projection ofvisual images, and individually projecting infrared light from at leastone or more infrared light projector means associated with correspondingareas on a screen in accordance with the received information wherebyenabling the infrared light to be incident into an imaging means of aperson conducting an unauthorized act:

[0096] This method is a method for acquiring information relating tomethod (6c) via the network and controlling the infrared light emission.With employing such method, it is also possible to attain an object ofenabling the record of the infrared light image at the partial areas byadaptively projecting the infrared light to the screen surface at thepartial areas having the low brightness. The information may be receivedin synchronization with the output of visual images when the output ofthe main feature program to the screen is performed only once. When theoutput of the main feature program is repeated plural times, thepredetermined information (information indicating area and time in whichbrightness of the screen becomes equal to or less than the predeterminedbrightness value) may be received every time the output is performed.Alternatively, it is also possible to acquire the predeterminedinformation in real-time for the first time and use the informationrecorded when it is received in the first time for the subsequentoutputs. Of course, it is also possible to combine this method with theabove-cited methods (1)-(5).

[0097] (6g) Method for projecting infrared light from at least one ormore infrared light projector means during a period of shielding theprojection light with a frame transferring shutter when the visual imageis projected from a film type projector means whereby enabling theinfrared light to be incident into an imaging means of a personconducting an unauthorized act:

[0098] This method is a unique one for a case when the film typeprojection is utilized. Namely, the present embodiment is focused onfeatures of closing the frame transferring shutter so as to shield theprojection light when the film frame is transferred. The presentembodiment ensures the recording of the infrared light image byprojecting the infrared light during a period when the frametransferring shutter has been closed for considering a decrease of thescreen surface brightness. With utilizing such method, it is possible toaccomplish an object of recording the infrared light image. The periodof shielding the projection light with the frame transferring shuttermay be detected or predicted from a frame transferring motion, or may bedetected or predicted from a motion of the frame transferring shutter.Of course, it is also possible to combine this method with theabove-cited methods (1)-(5).

[0099] (7) As a imaging prevention method for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The method is for projecting infrared light from at least oneor more infrared light projector means disposed in a vicinity of thescreen whereby enabling the infrared light reflected on the screen toincident into an imaging means of a person conducting the unauthorizedact.

[0100] This method shares the same principle as an conventional systemon features wherein the infrared light is projected toward the screenfrom the vicinity of the screen front whereby enabling the reflectedinfrared light at the screen to incident into the imaging means of aperson conducting the unauthorized act. However, in this method, thedisposing location of the infrared light projector means is optimizedand set to the vicinity of the screen so as to increase an amount of theinfrared light reflected at the screen surface remarkably with respectto the conventional system.

[0101] With employing this configuration, the technical effectsubstantially the same as that of the conventional system may beobtained by using the infrared light projector means with less output Ifthe infrared light projector means with substantially the same output asthat of the conventional system is utilized, far greater preventioneffect may be obtained. In general, a greater prevention effect may beobtained by using a less output infrared light projector means.

[0102] (8) As an imaging prevention method for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The method is for automatically adjusting a projectiondirection of at least one or more infrared light projector meansdisposed in a vicinity of the screen in correspondence with size changeof the screen, and projecting infrared light to the adjusted projectiondirection whereby enabling the infrared light reflected on the screen toincident into an imaging means of a person conducting the unauthorizedact.

[0103] This method enables to secure the projection direction optimizedin accordance with the screen size by automatically adjusting theinfrared light projection direction (projection position of the infraredlight projected on the screen) coupled with the screen size change.Particularly, it is more important for the infrared light projectormeans projecting to a corner portion of the screen since there is apossibility of that the infrared light may not be contributed in theprevention of the unauthorized act when the screen size is changed. Theadjustment may be performed manually. According to the presentembodiment, an operational efficiency may be improved since an operatoronly has to consider the screen size change. The infrared lightprojector means is not limited to ones disposed in the vicinity of thescreen.

[0104] (9) As a system for interfering unauthorized imaging of visualimages projected onto a screen, the following is provided. In thesystem, at least one or more infrared light projector means are disposedat a rear side of the screen viewing from viewer/audiences and infraredlight is projected from the at least one or more infrared lightprojector means to a viewer/audience direction whereby enabling theinfrared light to enter an imaging means of a person conducting theunauthorized act.

[0105] This system corresponds to the above-cited method (1). That is,the system enables to project infrared light from the rear side of thescreen and enables the infrared light to efficiently enter the imagingmeans of a person conducting the unauthorized act without requiring thereflection at the screen surface. The description of (1) also applies tothis system.

[0106] (10) As a system for interfering unauthorized imaging of visualimages projected onto a screen, the following is provided. In thesystem, at least one or more infrared light projector means are disposedat a front side of the screen viewing from viewer/audiences and infraredlight is projected from the at least one or more infrared lightprojector means to a viewer/audience direction whereby enabling theinfrared light to directly enter an imaging means of a person conductingthe unauthorized act.

[0107] This system corresponds to the above-cited method (2). That is,the system enables to project infrared light from the front side of thescreen and enables the infrared light to efficiently enter the imagingmeans of a person conducting the unauthorized act without requiring thereflection at the screen surface. The description of (2) also applies tothis system.

[0108] (11) As a system for interfering unauthorized imaging of visualimages projected onto a screen, the following is provided. In thesystem, at least one or more infrared light projector means are disposedin a vicinity of the screen and infrared light is projected from the atleast one or more infrared light projector means to a viewer/audiencedirection whereby enabling the infrared light to enter an imaging meansof a person conducting the unauthorized act.

[0109] This system corresponds to the above-cited method (3). That is,the system enables to project infrared light from in the vicinity of thescreen and enables the infrared light to enter the imaging means of aperson conducting the unauthorized act without requiring the reflectionat the screen surface. The description of (3) also applies to thissystem.

[0110] (12) As a system for interfering unauthorized imaging of visualimages projected onto a screen, the following is provided. The systemcomprises at least one or more infrared light projector means forprojecting infrared light, and infrared light reflection means forreflecting infrared light projected from the at least one or moreinfrared light projector means so as the infrared light directlyincident into an imaging means of a person conducting the unauthorizedact.

[0111] This system corresponds to the above-cited method (4). That is,the system enables to increase an amount of the infrared light enteringto the imaging means of a person conducting the unauthorized act byutilizing the infrared light reflection means actively reflecting theinfrared light. The description of (4) also applies to this system.

[0112] A driving technique of driving means for variably controlling theinfrared light reflection means or its reflection surface may not belimited to particular ones. Further, it is not necessary to control thereflection surface of the infrared light reflection means so as that awhole area of the reflection surface is directed to the same direction.Alternatively, when the reflection surface is divided into a plural ofsections and each of the sections is independently controllable, each ofthe sections may be controlled to direct a different direction.

[0113] (13) As a system for interfering unauthorized imaging of visualimages projected onto a screen, the following is provided. The systemcomprises at least one or more infrared light projector means forprojecting infrared light, and emission control means for controllingthe at least one or more infrared light projector means to emitintermittently so as an imaging means of a person conducting theunauthorized act records a predetermined pattern of the intermittentemission.

[0114] This system corresponds to the above-cited method (5). That is,the system enables to force recording of the emission pattern irrelevantto the main feature of the program illegally recorded by intermittentlyemitting the infrared light. The description of (5) also applies to thissystem.

[0115] The emission control means may be, for example, an electroniccircuit such as a computer, an IC for specific purpose, switching meansfor switch-controlling the emission according to a clock or its dividedfrequency output, switching means for switch-controlling the emissionaccording to charging/discharging of a capacitor or the like, or,switching means for switch-controlling the emission by a mechanicalstructure or the like. Of course these function may be realized withusing software or hardware. This system may include systemscorresponding to methods (5a)-(5e).

[0116] (13a) System utilizing emission control means for enabling atleast one or more infrared light projector means to emit intermittentlyin accordance with a predetermined code information so as that animaging means of a person conducting the unauthorized act recordsinformation along a time axis, instead of using the emission controlmeans of (13):

[0117] This system corresponds to the above-cited method (5a). That is,in this system, the information is superposed on the emission timingitself. The description of (5a) also applies to this system.

[0118] (13b) System utilizing emission control means for controlling aplurality of infrared light projector means to emit intermittently inrelay format in accordance with a predetermined code information so asthat an imaging means of a person conducting the unauthorized actrecords information along a time axis, instead of using the emissioncontrol means of (13):

[0119] This system corresponds to the above-cited method (5b). That is,in this system, the emission timing itself may have meanings in somecase, and it is also possible to superpose the desired information onlocations of the recorded light images themselves. The description of(5b) also applies to this system.

[0120] (13c) System utilizing emission control means for controlling aplurality of infrared light projector means to emit intermittently inrelay format in accordance with a predetermined code information so asthat an imaging means of a person conducting an unauthorized act recordsa two-dimensional information, instead of using the emission controlmeans of (13):

[0121] This system corresponds to the above-cited method (5c). That is,the system enables to clearly ascertain the record of thetwo-dimensional information (figure, notation, or any other identifiableforms) when light image positions are compressed in the time-axisdirection. The description of (5c) also applies to the system.

[0122] (13d) System utilizing emission control means for controlling aplurality of infrared light projector means to emit intermittently in apredetermined combination so as that an imaging means of a personconducting the unauthorized act records a two-dimensional information,instead of using the emission control means of (13):

[0123] This system corresponds to the above-cited method (5d). That is,the system enables to ascertain the record of light images in alllocations, that are spread in the time axis direction in the above-cited(13c), at the same display screen simultaneously by lighting them upaltogether. The description of (5d) also applies to this system.

[0124] (13e) System utilizing at least one or more infrared lightprojection unit comprising a plurality of light emitting devicesdisposed in an array for projecting infrared light, and an infraredlight projection control unit for individually controlling said lightemitting device of the infrared light projector means disposed in a rearside of the screen viewing from a viewer/audience side so as that animaging means of a person conducting an unauthorized act record apredetermined information corresponding to an emission pattern of theinfrared light:

[0125] This system corresponds to the above-cited method (5e). That is,this system is similar to embodiment (13d). Of course, the descriptionof (5d) also applies to the system. Further, the infrared lightprojection control unit may be, for example, an electronic circuit suchas a computer, an IC for specific purpose, switching means forswitch-controlling the emission according to a clock or its dividedfrequency output, switching means for switch-controlling the emissionaccording to charging/discharging of a capacitor or the like, or,switching means for switch-controlling the emission by a mechanicalstructure or the like.

[0126] (14) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The system comprises at least one or more infrared lightprojector means for projecting infrared light, and at least one or morelight sensors disposed in a rear side of the screen viewing from aviewer/audience side for detecting brightness of the facing screen,wherein a detection result of the light sensor is outputted to thecorresponding infrared light projector means as a light amount adjustingsignal for increasing an amount of the infrared light as the detectedbrightness of the screen surface decrease.

[0127] This system corresponds to the above-cited method (6). That is,this system enables to adaptively increase the amount of the infraredlight projected onto a scene or area of the screen surface having thelow brightness whereby enabling the infrared light to be easily recordedon an imaging means of a person conducting an unauthorized act. Thedescription of (6) also applies to this system.

[0128] For example, a photo-diode or a photo-transistor may be employedfor the light sensor. Further, this system may include systemscorresponding to methods (6a)-(6g).

[0129] (14a) As an imaging prevention system for interferingunauthorized imaging of visual image projected on a screen, thefollowing system is provided. The system comprises at least one or moreinfrared light projector means for projecting infrared light, at leastone or more light sensors disposed close to a backside of the screenviewing from a viewer/audience side, and an infrared light projectioncontrol unit for accepting output signals from the light sensors and forcontrolling the at least one or more infrared light projector means toproject the infrared light in case that a brightness of the screensurface facing the light sensor is equal or less than a predeterminedbrightness.

[0130] This system corresponds to the above-cited method (6a). That is,this system enables to project the infrared light onto a scene or areaof the screen surface having the low brightness based on the detectionresults of the screen surface brightness whereby enabling the infraredlight to be easily recorded on an imaging means of a person conductingan unauthorized act. The description of (6a) also applies to thissystem.

[0131] For example, electronic circuits such as a computer or an IC forspecific purpose may be employed as the infrared light projectioncontrol unit. More specifically, it requires memory means for recordinga predetermined value, comparison means for comparing the predeterminedvalue and the detection value, means for specifically controlling theemission of the infrared light projector means based on the comparisonresult.

[0132] In case that a plural of the comparison results are considered,corresponding functional means is required. For example, it furtherrequires means for counting the number of light sensors in which thebrightness equal or less than the predetermined number is detected,memory means for recording a predetermined number that becomes acomparison reference number, comparison means for comparing thesepredetermined numbers and actual measurement values (counting values)and so on when the infrared light projector means emit only in case thatthe number of areas in which the brightness is less than thepredetermined value is equal or bigger than a predetermined number insingle scene or a region to be detected.

[0133] Further, in case that, for example, emissions of the infraredlight projector means are switched in accordance with a distributionpattern of the areas in which the brightness is less than thepredetermined value over the screen, it further requires memory meansfor recording distribution patterns to be considered, determinationmeans for determining which of the distribution patterns is matched tothe measured pattern by comparing with the stored distribution patterns,means for specifying the infrared light projector means to beemission-controlled based on the determined distribution pattern, and soon. Of course, these functions may be realized by means of software orhardware. (14b) System utilizing an infrared light projection controlunit for individually controlling at least one or more infrared lightprojector means to project infrared light from the infrared lightprojector means associated with an area corresponding to the lightsensor from which the detection result is obtained in case that abrightness of the screen surface is equal or less than a predeterminedbrightness, instead of using the infrared light projection control unitof (14a):

[0134] This system corresponds to the above-cited method (6b). That is,this system enables to adaptively project the infrared light ontopartial areas of the screen surface having the low brightness wherebyenabling the infrared light image to be easily recorded not for wholearea of the screen but for partial areas. The description of (6b) alsoapplies to this system.

[0135] (14c) System utilizing reproducing means for reproducing timeinformation in which brightness at the screen becomes equal or less thana predetermined brightness value from a recording medium, and aninfrared light projection control unit for controlling projection ofinfrared light from the at least one or more infrared light projectormeans in accordance with the reproduced information, instead of usingthe light sensor and the infrared light projection control unit of(14a):

[0136] This system corresponds to the above-cited method (6c). That is,this system assumes a case in which the time periods of low brightnessare stored as information in the recording medium and not determined bythe measurement results. The system does not require the light sensor.The description of (6c) also applies to this system.

[0137] (14d) System utilizing reproducing means for reproducing area andtime information in which brightness at the screen becomes equal or lessthan a predetermined brightness value from a recording medium, and aninfrared light projection control unit for individually controllingprojection of infrared light from the at least one or more infraredlight projector means associated with corresponding areas of the screenin accordance with the reproduced information, instead of using thelight sensor and the infrared light projection control unit of (14a):

[0138] This system corresponds to the above-cited method (6d). That is,this system assumes a case in which the partial areas and the timeperiods of low brightness are stored as information in the recordingmedium and not determined by the measurement results. The system doesnot require the light sensor. The description of (6d) also applies tothis system.

[0139] (14e) System utilizing receiving means for receiving informationfrom a network for time in which brightness at the screen becomes equalor less than a predetermined brightness value in synchronization withthe projection of said visual image, and an infrared light projectioncontrol unit for controlling projection of infrared light from the atleast one or more infrared light projector means in accordance with thereceived information, instead of using the light sensor and the infraredlight projection control unit of (14a):

[0140] This system corresponds to the above-cited method (6e). That is,this system assumes a case in which the time periods of low brightnessare received via the network and not determined by the measurementresults. The system does not require the light sensor nor brightnessdetection means. The description of (6e) also applies to this system.

[0141] (14f) System utilizing receiving means for receiving informationfrom a network for area and time in which brightness at the screenbecomes equal or less than a predetermined brightness value insynchronization with the projection of visual image, and an infraredlight projection control unit for individually controlling projection ofinfrared light from the at least one or more infrared light projectormeans associated with corresponding areas on the screen in accordancewith the received information, instead of using the light sensor and theinfrared light projection control unit of (14a):

[0142] This system corresponds to the above-cited method (6f). That is,this system assumes a case in which the partial areas and the timeperiods of low brightness are received via the network and notdetermined by the measurement results. The system does not require todispose the light sensor. The description of (6f) also applies to thissystem.

[0143] (14g) System utilizing shielding period detection means fordetecting a period of shielding the projection light with a frametransferring shutter, and an infrared light projection control unit forcontrolling emission of the infrared light projector means based ondetection results of the shielding period detection means, instead ofusing the light sensor and the infrared light projection control unit of(14a):

[0144] This system corresponds to the above-cited method (6g). That is,this system ensures the recording of the infrared light image byprojecting the infrared light with consideration of a decrease in thescreen surface brightness during a period of the frame transferringshutter closing. The description of (6f) also applies to this system.

[0145] As the shielding period detection means, following methods may becontemplated. The method may be a method for mechanically detecting thefilm transfer, or a method for electronically detecting the filmtransfer using a change of electrostatic capacitance or the like, or amethod for mechanically detecting a motion of the shutter mechanism, ora method for electronically detecting a motion of the shutter mechanism.

[0146] (15) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The system is to dispose at least one or more infrared lightprojector means in a vicinity of the screen surface at a front side ofthe screen viewing from viewers/audiences so as the infrared lightreflected on the screen incident into an imaging means of a personconducting the unauthorized act.

[0147] This system corresponds to the above-cited method (7). That is,this system enables an ample amount of the reflected infrared lightincident into the imaging means of a person conducting the unauthorizedact by projecting the infrared light to the screen from locations at thevicinity of the screen. The description of (7) also applies to thissystem.

[0148] (16) As an imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the following isprovided. The system comprises at least one or more infrared lightprojector means disposed in a vicinity of the screen surface forprojecting infrared light to the screen, projecting direction actuatormeans for driving the infrared light projector means to vary itsprojecting direction, memory means for recording projecting directioninformation of each infrared light projector means according to a screensize, and projecting direction control means for reading out theprojecting direction information from the memory means when aninstruction to change the screen size is detected, for providing theread-out information to said projecting direction actuator means, andfor automatically adjusting a projecting direction of said infraredlight projector means.

[0149] This system corresponds to the above-cited method (8). That is,this system enables to provide the optimum projecting directionaccording to the screen size (aspect ratio) by automatically adjustingthe projecting direction of the infrared light in conjunction with thechange of the screen size. The description of (7) also applies to thissystem.

[0150] The system is suitable for a projection system having a pluralscreen sizes each suited for the visual image projection and required tochange the screen size when necessary. For example, in a commercialsystem such as a movie theater, the screen size (aspect ratio) may beStandard (1:1.33), Europe Vista (1:1.66), America Vista (1:1.85), Scope(1:2.35), and so on. These values are examples of some typical values,and not limited only to these values.

[0151] The projecting direction information stored in the memory meansmay be, for example, a horizontal angle, an elevation angle, or theother information. Of course, an amount of motion or the other controlvalues may be used instead of the angle. The projecting directionactuator means may comprise, for example, means for turning around anaxis to which the infrared light projection means is attached, means forrotating or horizontally transporting a base on which the infrared lightprojection means is fixed, or the other means. As the projectingdirection control means, a computer, an IC for specific purpose or theother electronic circuits may be used, for example.

[0152] (B) Specific Embodiment

[0153] In the following, the specific embodiments of imaging preventionmethod and system in accordance with the present invention will now bedescribed.

(1) FIRST EMBODIMENT EXAMPLE

[0154] The first embodiment example is shown in FIG. 1. This embodimentexample is related to a novel feature of projecting infrared light to aviewer/audience direction from a rear side of the screen. FIG. 1 showsan example applicable for a movie theater or other theater systems. Ofcourse, the technique itself may be applicable to a home theater. In anycases, the visual images projected onto the screen include televisionprograms and the other copyrighted products as well as a movie. Next, aspecific example of each apparatus composing the system shown in FIG. 1will now be described.

[0155] A projector apparatus 1 is a projection apparatus projectingvisual images to be viewed/listened onto a screen 2. The projectorapparatus 1 may be, for example, a film projector for projecting a moviefilm, a slide projector for projecting a slide, an overhead projector(OHP), a liquid crystal projector for directly projecting a digitalimage, a digital micro-mirror device (DMD) projector, a CRT projector orthe like.

[0156] Although, FIG. 1 shows a type in which the projector apparatus 1is disposed at a rear side of audience seats 4 and the reflected lightat the screen surface is viewed by viewers/audiences, a location of theprojector apparatus 1 is not limited to this particular one. Forexample, it is possible to contemplate that the projector apparatus 1may be disposed a front side of the audience seats 4 (namely, betweenthe screen 2 and the audience seats 4), or at above of the audienceseats 4, or at a side wall side. Of course, the projector apparatus 1may be disposed in a rear side of the screen 2 in case that visualimages are projected from the rear side of the screen and itstransmission light is viewed by the viewers/audiences (so-called a rearprojection type).

[0157] The screen 2 shown in FIG. 1 is a theater screen. In general,sound source holes (ventilation holes or any other structures connectingthe rear side and the front side) called as a sound perforation areformed so as to effectively propagate sound from the sound sourcedisposed at the rear side of the screen to the viewers/audiences side.An arbitrary shape or size or position may be selected for the soundperforation. FIG. 2 shows an example of the sound perforation. In thepresent specification, the sound perforation is used to transmitinfrared light from the rear side of the screen to the front side.

[0158] The screen 2 of FIG. 1 may be a screen without the soundperforation. In such case, it is preferred to have characteristics ofhaving a screen comprising a material capable of transmitting theinfrared light easily, or a screen with embedded members capable oftransmitting the infrared light easily, or a screen having parts ofthinner thickness than the rest of the screen.

[0159] An infrared light projector apparatus 3 is a projector apparatusprojecting an infrared light to prevent unauthorized imaging of visualimages projected onto the screen. It utilizes features of that theinfrared light is not recognized by the viewers/audiences while sensedby CCD (solid state imaging device) of an imaging apparatus. It ispossible to contemplate that the infrared light projector apparatus 3may be, for example, a light emitting diode or any other devicesemitting light flux mainly comprising of the infrared light, or a deviceof type in which an infrared light transmission filter is disposed at alight path and only the infrared light is finally outputted, or a deviceof type in which a visible light cut-filter and/or an ultra-violetcut-filter are disposed at a light path and only the infrared light isfinally outputted.

[0160] It is considered that a typical location of the infrared lightprojector apparatus 3 is at a vicinity of the rear side of the screen.The position may be set an arbitrary location provided that the infraredlight projector apparatus 3 is disposed at the rear side of a virtualreference plane including the screen surface viewing from the audienceseats 4. For example, the infrared light projector apparatus 3 may bedisposed at obliquely rear side of the screen (outside of the screen 2frame) whereby a part or all of the infrared light may pass throughspace outside of the screen and be projected to the audience seats 4.The infrared light projector apparatus 3 may be embedded in the screenitself.

[0161] The infrared light projector apparatus 3 may be disposed in anyarbitrary height provided that it is disposed at the rear space of thescreen. The infrared light projector apparatus 3 may be positioned in avicinity of the lower section of the screen 2 (height of the infraredlight projector apparatus 3 may be higher or lower than the bottom hemof the screen 2) or in a vicinity of the middle section of the screen 2,or in a vicinity of the upper section of the screen 2 (height of theinfrared light projector apparatus 3 may be higher or lower than the tophem of the screen 2). The optimum height of the infrared light projectorapparatus 3 may vary depending on a relationship of the audience seats 4and the screen 2. In general, the infrared light projector apparatus 3may be disposed within an imaging area (or imaging angle) of the imagingapparatus used for the unauthorized imaging.

[0162] The projecting direction of the infrared light may be setarbitrary provided that the projected light flux is directed to an areaor space at where the unauthorized imaging may take place. At least, thefollowing directions may be selected. The directions is such that theprojected light flux can cover a region with a certain height where theimaging without any interference is possible within the area in whichthe audience seats 4 are disposed. For example, in case that theinfrared light projector apparatus 3 are disposed at vicinities of bothright and left side edges of the screen 2 as shown in FIG. 3, theinfrared light may be projected to obliquely front directions from theirlocations. Further, in case that the infrared light projector apparatus3 is disposed at a vicinity of the top section of the screen 2, theprojecting direction of the infrared light becomes an obliquely downwarddirection. In order to increase the prevention effect, it is preferableto arrange a light axis of the optical system in the imaging apparatusused for the unauthorized act and a light axis of the infrared light insuch a way that both light axes become as parallel as possible.

[0163] Alternatively, in case that the light axis of the infrared lightis changed by utilizing the infrared light reflection mirror (so-calledhot mirror) or any other infrared light reflection unit, the light axisof the reflected infrared light may be needed to be directed to theabove-mentioned region or space. Instead of reflecting the infraredlight by the reflection mirror as mentioned in the above, the projectionlight axis of the reflected infrared light may be directed to theabove-mentioned region or space by driving the infrared light projectorapparatus 3 itself For example, the infrared light projector apparatus 3may be driven in a horizontal direction so as that the reflected lightscans the audience side.

[0164] In any of the above-cited cases, it is preferable to determinedisposition (location and height) of the infrared light projectorapparatus or projecting direction so as to reduce an angle differencebetween the optical axis of the imaging apparatus and the light axis ofthe infrared light as much as possible. This is because the infraredlight becomes easier to be recorded and the prevention effect becomeslarger when the angle difference between the optical axis of the imagingapparatus and the light axis of the infrared light is smaller. The samethings applies to the other embodiments.

[0165] Further, the infrared light may be a spread light having spreadlight flux, or a spot light having a tightened light flux.Alternatively, the infrared light may be projected to focus on thescreen so as that a predetermined information (for example, outputdate/time, output location, screen number, output apparatus, outputperformer, or any other information required to identify a location inwhich the unauthorized act is performed) or character information(include marks and any other identifiable graphic information) may berecorded. Although it is a typical to use a constant emission (light on)for the infrared light providing these information, it is possible toprovide a predetermined information by a technique of intermittentlyemitting the infrared light.

[0166] In addition to the above, the infrared light projection methodmay include a method for emitting the infrared light intermittently. Byintermittently projecting the infrared light, the viewing becomesdifficult since the brightness of the recorded screen variesindependently with respect to visual images of the main feature of aprogram. It is also possible to enable reading out of desiredinformation from appearance timings or appearance locations of therecorded light images by controlling the timing of the intermittentemission or the emission location of the infrared light projectorapparatus 3. Any arbitrary intermittent emission methods described abovemay be utilized. Concrete emission methods will be described with theother embodiments in the following.

[0167] The number of the infrared light projector apparatus 3 is notlimited to one. For example, FIG. 1 or FIG. 3 show cases where two ofthe infrared light projector apparatus 3 are used. Of course, three ormore of the infrared light projector apparatus 3 may be disposed atdiscretion. FIG. 1 or FIG. 3 seems to show the infrared light projectorapparatus 3 with single infrared light emission device. However, aplurality of the infrared light emission devices may also be mounted onthe single infrared light projector apparatus 3. In this case, asimultaneous emission control of all the infrared light emission devicesor an individual emission control may be performed at discretion.

[0168] The amount of the infrared light entering the imaging apparatusmay be increased by projecting the infrared light to the audience seatsfrom the rear side of the screen 2 as the present embodiment, morespecifically by disposing the imaging apparatus for imaging visualimages projected on the screen in the unauthorized manner and theinfrared light projector apparatus 3 for projecting the infrared lightto prevent such unauthorized imaging in a face-to-face position and byprojecting the infrared light to directly incident into the imagingapparatus from the infrared light projector apparatus 3.

[0169] Consequently, the prevention effect greater than that of aconventional system may be expected. Further, the infrared lightprojector apparatus 3 having a emission brightness (output) less thanthe conventional system may be used when only the comparable preventioneffect is required. Accordingly, an economical effect may be promoted inthe apparatus or its system.

[0170] In case that the infrared light transmits through the screens theprevention effect greater than a conventional system may be realized byutilizing a screen allowing easy transmission of the infrared light (forexample, by utilizing a screen having material itself transmits easily,or a screen in which members having a high transmittance for theinfrared light are partially embedded, or a screen in which concavedportions are partially formed for easy transmission of the infraredlight). Particularly, in case that the screen capable of easytransmission of the infrared light is used, the present embodimentexample has a far greater merit since ample amount of the reflectedlight may not be anticipated for application of the conventional system.For example, in case that a rear projection type projector apparatus isincluded in the system, desired effect may not be obtained even when theconventional system is applied.

[0171] As described above, the system according to the presentembodiment can achieve the prevention effect greater than theconventional system regardless of the infrared light paths to the frontarea or space of the screen.

(2) SECOND EMBODIMENT EXAMPLE

[0172] The second embodiment example is shown in FIG. 4. This embodimentexample is related to a novel feature of projecting infrared light to aviewer/audience direction from a front side of the screen. FIG. 4 alsoshows an example applicable for a movie theater or other theatersystems. Similar to the first embodiment example, the technique itselfmay be applicable to a home theater. Of course, the visual imagesprojected onto the screen include television programs and the othercopyrighted products as well as a movie. Next, a specific example ofeach apparatus composing the system shown in FIG. 4 will now bedescribed. Here, an explanation of the projector apparatus 1 is omittedsince it is similar to the first embodiment example.

[0173] Contrary to the first embodiment example, the screen 2 may haveany arbitrary construction. That is, the screen of FIG. 4 may be ascreen having a configuration capable of easily transmitting theinfrared light, or a screen having a configuration capable oftransmitting the infrared light, or a screen incapable of transmittingnor passing through the infrared light. This is because that theinfrared light projector apparatus 3 is disposed in the front of thescreen 2 and an existence of the screen does not interfere the incidentof the infrared light into the imaging apparatus.

[0174] An apparatus construction itself of the infrared light projectorapparatus 3 is the same as that of the first embodiment example.Differences are a location and a projection method of the infrared lightprojector apparatus 3 and so on. It is considered that a typicallocation of the infrared light projector apparatus 3 is at a vicinity ofthe both sides of the screen so as not to interfere the viewing of themain feature program. However, the position may be set an arbitrarylocation provided that the infrared light projector apparatus 3 isdisposed at an audience seat side from the virtual reference planeincluding the screen surface.

[0175] For example, it may be disposed at a vicinity of the center ofthe screen's bottom hem below an area onto which the visual images areprojected. Similarly, it may be disposed at a vicinity of the center ofthe screen's top hem above an area onto which the visual images areprojected. Alternatively, it may be disposed at a side wall part in theaudience seat side from the virtual reference plane including the screensurface. For the theater system such as a movie theater, it may beembedded in such a way that the infrared light can be projected to theopposite side of the screen at above the seat's backrest portion. Incase that such construction is utilized, a great prevention effect maybe anticipated since the infrared light may be projected from a closerange to the imaging apparatus even when the infrared light projectorapparatus 3 with rather low output is used. Alternatively, the infraredlight projector apparatus 3 may be disposed at a ceiling above theaudience seat. It is preferred to mount the infrared light projectorapparatus 3 on a surface (audience side plane) of the screen 2 if itdoes not interfere the viewing.

[0176] Further, similar to the first embodiment example, a dispositionheight of the infrared light projector apparatus 3 is not limited to anyparticular value. The optimum height of the infrared light projectorapparatus 3 may vary depending on a relationship of the audience seats 4and the screen 2. In general, the infrared light projector apparatus 3may be disposed within an imaging area (or imaging angle) of the imagingapparatus used for the unauthorized imaging.

[0177] Similarly, the projecting direction of the infrared light may bearbitrary determined provided that the projected light flux is directedto an area or space at where the unauthorized imaging may take place. Atleast, the following directions may be selected. The directions is suchthat the projected light flux can cover a region with a certain heightwhere the imaging without any interference is possible within the areain which the audience seats 4 are disposed. Alternatively, in case thatthe light axis of the infrared light is changed by utilizing theinfrared light reflection mirror (so-called hot mirror) or any otherinfrared light reflection unit, the light axis of the reflected infraredlight may be needed to be directed to the above-mentioned region orspace. Instead of reflecting the infrared light by the reflection mirroras mentioned the above, the light axis of the reflected infrared lightmay be directed to the above-mentioned region or space by driving theinfrared light projector apparatus 3 itself. For example, the infraredlight projector apparatus 3 may be driven in a horizontal direction soas that the reflected light scans the audience side.

[0178] Also in the above-cited cases, it is preferable to determinedisposition (location and height) of the infrared light projectorapparatus or projecting direction so as to reduce an angle differencebetween the optical axis of the imaging apparatus and the light axis ofthe infrared light as much as possible. This is because the infraredlight becomes easier to be recorded and the prevention effect becomeslarger when the angle difference between the optical axis of the imagingapparatus and the light axis of the infrared light is smaller.

[0179] Further, the infrared light may be a spread light having spreadlight flux, or a spot light having a tightened light flux. The infraredlight may be a constantly emitted (light on) or an intermittentlyemitted. By intermittently projecting the infrared light, the viewingbecomes difficult since the brightness of the recorded screen variesindependently with respect to visual images of the main feature of aprogram. Intervals of the intermittent emission may be varied at random.By changing the emission interval randomly, it is possible to preventelimination of the brightness changes from the visual images imaged bythe unauthorized manner even with using image processing.

[0180] It is also possible to enable reading out of desired informationfrom appearance timings or appearance locations of the light images bycontrolling the timing of the intermittent emission, or by controllingemission positions of the infrared light projector apparatus 3 when aplurality of the infrared light projector apparatus 3 are used. Anyarbitrary intermittent emission methods described above may be utilized.Concrete emission methods will be described with the other embodimentsin the following.

[0181] Also in this embodiment example, the number of the infrared lightprojector apparatus 3 is not limited to one. For example, FIG. 4 showcases where two of the infrared light projector apparatus 3 are used. Ofcourse, three or more of the infrared light projector apparatus 3 oronly one of the infrared light projector apparatus 3 may be disposed.FIG. 4 seems to show the infrared light projector apparatus 3 withsingle infrared light emission device. However, a plurality of theinfrared light emission devices may also be mounted on the singleinfrared light projector apparatus 3. In this case, a simultaneousemission control of all the infrared light emission devices or anindividual emission control may be performed at discretion.

[0182] The amount of the infrared light entering the imaging apparatusmay be increased more than the first embodiment example by projectingthe infrared light to the audience seats from the front side of thescreen 2 as the present embodiment, more specifically by disposing theimaging apparatus for imaging visual images projected on the screen inthe unauthorized manner and the infrared light projector apparatus 3 forprojecting the infrared light to prevent such unauthorized imaging in aface-to-face position and by projecting the infrared light to directlyincident into the imaging apparatus from the infrared light projectorapparatus 3 at closer range than the first embodiment example.

[0183] Consequently, the prevention effect greater than that of aconventional system may be expected. Further, the infrared lightprojector apparatus 3 having a emission brightness (output) less thanthe conventional system may be used when only the prevention effectcomparable to that of the conventional system is required. Accordingly,an economical effect may be promoted in the apparatus or its system.

[0184] In case that the infrared light transmits through the screen, theprevention effect greater than a conventional system may be realizedsince no reflection at the screen surface is required in the presentembodiment while only the less than the adequate amount of thereflection light is anticipated in the conventional system technique.For example, in case that a rear projection type projector apparatus isincluded in the system, desired effect may not be obtained even when theconventional system is applied.

[0185] As described above, the system according to the presentembodiment can achieve the prevention effect greater than theconventional system regardless of the infrared light paths to the frontarea or space of the screen.

(3) THIRD EMBODIMENT EXAMPLE

[0186] The third embodiment example is shown in FIG. 5 and FIG. 6. Thisembodiment example is related to a novel feature of projecting infraredlight to a viewer/audience direction from a side of the screen. FIG. 5show an example of case in which the infrared light projector apparatus3 is disposed outside (above) the top hem of the screen 2. FIG. 6 showan example of case in which the infrared light projector apparatus 3 aredisposed outside (above) the top hem of the screen 2 and outsides ofboth left and right sides. All of figures shows application examples forthe movie theater or any other theater system.

[0187] Similar to the first embodiment example, the technique itself maybe applicable to a home theater. Of course, the visual images projectedonto the screen include television programs and the other copyrightedproducts as well as a movie. Next, a specific example of each apparatuscomposing the system shown in FIG. 5 and FIG. 6 will now be described.Here, an explanation of the projector apparatus 1 is omitted since it issimilar to the first embodiment example.

[0188] The screen 2 with the same construction as the second embodimentexample is used. That is, the screen may be a screen having aconfiguration capable of easily transmitting the infrared light, or ascreen having a configuration allowing infrared light pass-through, or ascreen incapable of transmitting nor passing through the infrared light.This is because that the infrared light projector apparatus 3 isdisposed around the screen 2 and an existence of the screen does notinterfere the incident of the infrared light into the imaging apparatus.

[0189] An apparatus construction itself of the infrared light projectorapparatus 3 is the same as that of the first embodiment example.Differences are a location and a projection method of the infrared lightprojector apparatus 3 and so on. It is considered that a typicallocation of the infrared light projector apparatus 3 is in a vicinity ofthe outer peripheral of the screen. Because the closer to an area towhich the main feature program is projected, it is easier for theprojected infrared light to be recorded in a typical case (inside theimaging area to be directly recorded, or higher probability to affectthe imaging area) whereby promote the prevention effect. The preventioneffect may not be necessary to be decreased even at space outside thescreen outer peripheral since the probability of the infrared lightrecording is relative one determined by a relationship with an imagingangle of the imaging apparatus.

[0190] For example, as shown in FIG. 5, the infrared light may be easilyprojected over a wide range of area when two of the infrared lightprojector apparatus 3 are disposed in such a way that the infrared lightprojector apparatus 3 are contacting on the screen's top hem. Foranother example, as shown in FIG. 6, dead angles of the preventableareas, caused by mismatching of the light axes of the projected infraredlights and the optical system axis of the imaging apparatus, may becovered when a plurality of the infrared light projector apparatus 3 aredisposed in such a way that the infrared light projector apparatus 3 arecontacting on the screen's top hem and single infrared light projectorapparatus 3 is disposed in both sides (light and left) of the screen.For an example of FIG. 6, the infrared light projected from the top partof the screen may not incident into the imaging apparatus positioned inthe back side of the audience seats (particularly in FIG. 6, slanting ofthe audience seat floor may also be one of the causes). However, theample amount of the infrared light may be directly projected to theaudience seats located in the back side by projecting the infrared lightfrom the both sides (right and left) whereby eliminating the dead anglesof the preventable areas in the system as a whole. In order to produceno dead angle in the audience seats in the top front row, it iseffective to dispose the infrared light projector apparatus at outsidethe screen's bottom hem or to combine with the first embodiment exampletechnique, namely the technique in which the infrared light is projectedfrom the rear side of the screen.

[0191] Further, similar to the first embodiment example or the secondembodiment example, a disposition height of the infrared light projectorapparatus 3 is not limited to any particular value. The optimum heightof the infrared light projector apparatus 3 may vary depending on arelationship of the audience seats 4 and the screen 2.

[0192] Similarly, the projecting direction of the infrared light may bearbitrary determined provided that the projected light flux is directedto an area or space at where the unauthorized imaging may take place. Atleast, the following directions may be selected. The directions is suchthat the projected light flux can cover a region with a certain heightwhere the imaging without any interference is possible within the areain which the audience seats 4 are disposed. Alternatively, in case thatthe light axis of the infrared light is changed by utilizing theinfrared light reflection mirror (so-called hot mirror) or any otherinfrared light reflection unit, the light axis of the reflected infraredlight may be needed to be directed to the above-mentioned region orspace. Instead of reflecting the infrared light by the reflecting mirroras mentioned the above, the light axis of the reflected infrared lightmay be directed to the above-mentioned region or space by driving theinfrared light projector apparatus 3 itself. For example, the infraredlight projector apparatus 3 may be driven in a horizontal direction soas that the reflected light scans the audience side.

[0193] Also in the above-cited case, it is preferable to determinedisposition (location and height) of the infrared light projectorapparatus or projecting direction so as to reduce an angle differencebetween the optical axis of the imaging apparatus and the light axis ofthe infrared light as much as possible. This is because the infraredlight becomes easier to be recorded and the prevention effect becomeslarger when the angle difference between the optical axis of the imagingapparatus and the light axis of the infrared light is smaller.

[0194] Further, the infrared light may be a spread light having spreadlight flux, or a spot light having a tightened light flux. The infraredlight may be a constantly emitted (light on) or an intermittentlyemitted. By intermittently projecting the infrared light, the viewingbecomes difficult since the brightness of the recorded screen variesindependently with respect to visual images of the main feature of aprogram. It is also possible to enable reading out of desiredinformation from appearance timings or appearance locations of therecorded light images by controlling the timing of the intermittentemission, or by controlling emission positions when a plurality of theinfrared light projector apparatus 3 are used. Any arbitraryintermittent emission methods described above may be utilized. Concreteemission methods will be described with the other embodiments in thefollowing.

[0195] Also in this embodiment example, the number of the infrared lightprojector apparatus 3 is not limited to one. For example, FIG. 5 showcases where two of the infrared light projector apparatus 3 are used. Ofcourse, three or more of the infrared light projector apparatus 3 oronly one of the infrared light projector apparatus 3 may be disposed.FIG. 5 seems to show the infrared light projector apparatus 3 withsingle infrared light emission device. However, a plurality of theinfrared light emission devices may also be mounted on the singleinfrared light projector apparatus 3. In this case, a simultaneousemission control of all the infrared light emission devices or anindividual emission control may be performed at discretion.

[0196] The amount of the infrared light entering the imaging apparatusmay be increased more than the first embodiment example by projectingthe infrared light to the audience seats from the vicinity of the screen2 as the present embodiment, more specifically by disposing the imagingapparatus for imaging visual images projected on the screen in theunauthorized manner and the infrared light projector apparatus 3 forprojecting the infrared light to prevent such unauthorized imaging in aface-to-face position and by projecting the infrared light to directlyincident into the imaging apparatus from the infrared light projectorapparatus 3 at closer range than the first embodiment example.

[0197] Consequently, the prevention effect greater than that of aconventional system may be expected. Further, the infrared lightprojector apparatus 3 having a emission brightness (output) less thanthe conventional system may be used when only the prevention effectcomparable to that of the conventional system is required. Accordingly,an economical effect may be promoted in the apparatus or its system.

[0198] In case that the infrared light transmits through the screen, theprevention effect greater than a conventional system may be realizedsince no reflection at the screen surface is required in the presentembodiment while only the less than the adequate amount of thereflection light is anticipated in the conventional system technique.For example, in case that a rear projection type projector apparatus isincluded in the system, desired effect may not be obtained even when theconventional system is applied.

[0199] As described above, the system according to the presentembodiment can achieve the prevention effect greater than theconventional system regardless of the infrared light paths to the frontarea or space of the screen.

(4) FOURTH EMBODIMENT EXAMPLE

[0200] The fourth embodiment example is shown in FIG. 7. This embodimentexample is related to a novel feature of projecting infrared light to ainfrared light reflection mirror 5 having a high reflection ratio andfor enabling the reflected light incident into the imaging apparatus ofa person conducting the unauthorized act. In a system shown in FIG. 7, areflection direction itself may be variable by driving the infraredlight reflection mirror 5 with an actuator apparatus 6.

[0201]FIG. 7 shows an application example of a movie theater or anyother theater systems. Similar to the first embodiment example, thetechnique itself may also be applicable to a home theater. Of course,the visual images projected onto the screen include television programsand the other copyrighted products as well as a movie. Next, a specificexample of each apparatus composing the system shown in FIG. 7 will nowbe described. Here, an explanation of the projector apparatus 1 isomitted since it is similar to the first embodiment example.

[0202] The screen 2 may be different depending at where the infraredlight reflection mirror 5 is disposed. In the example of FIG. 7, theinfrared light reflection mirror 5 is disposed in a vicinity of thescreen 2. Accordingly, the same construction may be applied as the thirdembodiment example when the reflection surface is identified as theprojection source of the infrared light. In this case, any arbitrarymaterials or constructions may be used as the screen of the thirdembodiment example. The same applies to a case of disposing the infraredlight reflection mirror 5 in the front of the screen 2.

[0203] In case that the infrared light reflection mirror 5 is disposedin the rear side of the screen so as that the reflected light isprojected to the audience seat side via passing or transmitting throughthe screen 2, the particular construction or material should be used asthe screen of the first embodiment example. Alternatively, any arbitraryconstructions may be applied to the screen 2 as the second embodimentexample and the third embodiment example even in case that the infraredlight reflection mirror 5 is disposed in the rear side of the screenprovided that the reflected light passes through space outside of thescreen.

[0204] An apparatus construction itself of the infrared light projectorapparatus 3 is the same as that of the first embodiment example.Differences are a location and a projection method of the infrared lightprojector apparatus 3 and so on. A disposition location of the infraredlight projector apparatus 3 may be determined by a relationship with thereflection surface of the infrared light reflection mirror 5.

[0205] For example, the infrared light projector apparatus 3 is disposedcloser to the audience seat side than the infrared light reflectionmirror 5 whatever the physical relationship of the infrared lightreflection mirror 5 and the screen 2 may be provided that the reflectionsurface of the infrared light reflection mirror 5 is positioned parallelor substantially parallel to the screen 2 as shown in FIG. 7. Of course,this is to direct the reflected light to the audience seat direction.

[0206] On the other hand, the infrared light projector apparatus 3 isdisposed the back side of the infrared light reflection mirror 5(viewing from the audience seat side to the screen direction) whateverthe physical relationship of the infrared light reflection mirror 5 andthe screen 2 may be provided that the reflection surface of the infraredlight reflection mirror 5 is positioned perpendicular or substantiallyperpendicular to the screen 2. In this case, an incident angle (anglewith respect to the normal direction of the reflection surface) of theinfrared light typically becomes larger with respect to the reflectionsurface.

[0207] In any of the above cited cases, the infrared light is projectedfrom the infrared light projector apparatus 3 so as that the infraredlight reflected shines over at least a part of areas or regions in whichthe unauthorized act may be performed. The positional relationship ofthe reflection surface and the screen is not limited to the above cases,and the positional relationship falls in somewhere in the middle of theabove cases may also be utilized. Of course, the optimum position or theoptimum projection direction of the infrared light projection apparatus3 may be different depending on the physical relationship with thereflection surface of the infrared light reflection mirror 5.

[0208] In an example of FIG. 7, the reflection direction of the infraredlight may be configured as variable even that the projecting directionof the infrared light projector apparatus 3 is fixed since the infraredlight reflection mirror 5 (reflection surface) may be driven with theactuator apparatus 6 whereby producing no dead angle in the imagingpreventable area.

[0209] The infrared light reflection mirror 5 (reflection surface) isconfigured as movable in this embodiment example, no dead angle may beproduced in the imaging preventable area even in case that the infraredlight reflection mirror 5 (reflection surface) is fixed (namely, noactuator apparatus 6 is not included in the configuration) by disposinga plurality of the infrared light projector apparatus 3 in variouspositions and reflecting the infrared lights projected from each of theinfrared light projector apparatus 3. Alternatively, the reflectiondirection may be configured as variable by driving the infrared lightprojector apparatus 3 with the actuator apparatus 6 and reflecting bythe infrared light reflection mirror 5.

[0210] The infrared light reflection mirror 5 is a mirror with a highinfrared light reflection ratio. A high reflection ratio may bepreferred not only for the infrared light but also for light in theother frequency band. Of course, it is preferable to have low reflectionratio for visible light. In case that the infrared light reflectionmirror 5 is disposed at a location at which there is no possibility ofentering the visible light, the high reflection ratio for the visiblelight may cause no trouble.

[0211] The infrared light reflection mirror 5 may have a plate-typeshape or a shape like a concave or a convex mirror. In case that theconvex mirror is used, there is a merit of reflecting the infrared lightin a wide area even when the projecting direction of the infrared lightis fixed or a movable range of the infrared light reflection mirror 5 islimited (including a case of being fixed). In this case, a spread lightflux may be used for the infrared light to be projected.

[0212] The infrared light reflection mirror 5 may be a one-sided mirrorhaving single reflection surface only at one side, or two-sided mirrorhaving reflection mirrors in both sides. The infrared light reflectionmirror 5 may be constructed from single mirror or constructed asassembled body comprising a plurality of mirrors. For example, it may beconstructed by arraying a plurality of micro mirrors on a plane.Alternatively, it may be constructed by arraying a plurality of micromirrors so as to form a polyhedron body (including a sphere) as a whole.

[0213] When the infrared light reflection mirror 5 has the polyhedronform, it is possible to be used for reflecting single light flux into aplurality of directions even the infrared light reflection mirror 5 isfixed. Of course, in case that the polyhedron form is employed andmoved, the reflection light may be reflected to a wide area by largelychanging angles of the reflection surfaces with a small amount of themovement.

[0214] Although the infrared light reflection mirror 5 is utilized inFIG. 7, the reflection surface is not necessary to have a mirror surfaceprovided that it can reflect the infrared light with a high reflectionratio. That is, means for reflecting the infrared light may include notonly the infrared light reflection apparatus but also a scattering plateor the like.

[0215] Further, only one infrared light reflection mirror 5 is disposedat a vicinity of the center of the screen's top hem in FIG. 7. However,the disposition and the number of the infrared light reflection mirror 5are not limited to those of FIG. 7. For example, it may be disposed in avicinity of the center of the screen's bottom hem, or in vicinities ofboth sides (right and left hem) of the screen. Of course, it is notlimited to the center vicinity of each hem but may be disposed in anypositions. Further, it may disposed not only at the vicinity of thescreen but disposed by a side wall or ceiling, or the front or rear sideof the screen, or any other various positions. Of course, the number isnot limited to one but the infrared light reflection mirror 5 may bedisposed in a plurality of positions.

[0216] The actuator apparatus 6 is means for changing the reflectiondirection of the infrared light by driving the infrared light reflectionmirror 5 or its reflection surface. FIG. 8 shows an example of theactuator apparatus. The apparatus shown in FIG. 8 has a motor 6A and arotation axis 6B as principle units. In case of FIG. 8, the infraredlight reflection mirror 5 mounted on the rotation axis 6B isrotationally driven to one direction (360 degree) by the motor 6A. Thatis, it becomes possible to horizontally scan the audience seat side withthe infrared light by changing the angle of the reflection surface (theinfrared light reflection mirror 5 itself in case of FIG. 8).

[0217] An appropriate value of the rotation angle or the rotation speedis selectively used in accordance with effects to be achieved. Forexample, the following drive method may be used. The method is to drivethe infrared light reflection mirror 5 in reciprocating manner withinthe minimum range (for example 90 degree) required for scanning theaudience seats with the reflected light. The driving speed may be a lowspeed such that single infrared light scanning is completed within aperiod of plural frames to a high speed such that plural infrared lightscanning are performed within a period of single frame. A difference ofthe driving speed relates to a frequency of the light image appearancein the visual images imaged in the unauthorized manner.

[0218] In case of the actuator apparatus of FIG. 8, it is shown a casethat the drive axis of the actuator apparatus 5 is a single-axis.However, it is also applicable to a case in which the drive axis is atwo-axis of different directions such as horizontal and verticaldirections. With increasing the drive axis having a different axisdirection, it is possible to expand the area to be covered by thescanning with the infrared light. Of course, the drive axis is notlimited to the two-axis, and may be the three-axis or more. Although themost simple actuator mechanism in which the infrared light reflectionmirror 5 is fixed on the rotation axis 6B of the motor 6A is shown inFIG. 8, a gear or any other mechanisms, or, a rubber or any otherelastic members may be utilized as means for transmitting power of themotor 6A. Further, it is possible to contemplate that the power sourcemay be ones using a rotational direction like the motor 6A, or onesusing a linear direction like a linear motor, or ones utilizing elasticwaves like a elastic wave motor, or ones utilizing an electromagnet, orthe like. For example, the infrared light reflection mirror 5 may bemoved horizontally along a hem of the screen 2 whereby moving the areailluminating the reflected infrared light.

[0219]FIG. 8 shows an example of the actuator apparatus in case that theinfrared light reflection mirror 5 is formed with single mirror.However, in case that the infrared light reflection mirror 5 is formedfrom a plurality of mirrors as means for reflecting the infrared light,it is possible to provide actuator apparatus for each of the reflectionmirrors to drive them independently.

[0220] The amount of the infrared light entering the imaging apparatusmay be increased more than the first embodiment example by disposing theinfrared light reflection mirror 5 that reflecting the infrared light tothe audience seats as the present embodiment, more specifically byreflecting the infrared light to the audience seats using the infraredlight reflection mirror 5 with a reflection ratio greater than thescreen.

[0221] Consequently, the prevention effect greater than that of aconventional system may be expected. Further, the infrared lightprojector apparatus 3 having a emission brightness (output) less thanthe conventional system may be used when only the prevention effectcomparable to that of the conventional system is required. Accordingly,an economical effect may be promoted in the apparatus or its system.

[0222] Further, it is possible to realize the effect of reflecting anintense infrared light in a wide range by means of driving the infraredlight reflection mirror 5 or its reflection surface with the actuatorapparatus 6 and by variably changing the reflection direction of theinfrared light reflected by the reflection surface. This effect may notbe realized with the conventional system having the fixed reflectionsurface.

[0223] In the present embodiment, it is described the case that thesingle plate of the infrared light reflection mirror 5 is driven so asto move the area illuminating the reflected light. However, thefollowing technique may also be utilized. The technique is to dispose aplurality of the infrared light projector apparatus 3 each having thedifferent projection direction (incident angle with respect to theinfrared light reflection mirror 5) of the infrared light and to controlthem to emit one by one so as to scan the audience seat side with thereflected light. Alternatively, the large area may be illuminated atonce by projecting to the single infrared light reflection apparatus 5from a plurality of the infrared light projector apparatus 3 having thedifferent projection directions (incident angle with respect to theinfrared light reflection mirror 5) of the infrared light.

(5) FIFTH EMBODIMENT EXAMPLE

[0224] The fifth embodiment example is shown in FIG. 9. This embodimentexample is related to a novel feature of enabling a recording of lightimage pattern irrelevant to the main feature program with the visualimages recorded in the unauthorized manner by intermittently emittingthe infrared light. This embodiment may be applicable to a conventionalsystem (system in which the infrared light is projected to the screen 2from a vicinity of the projector apparatus or any other distantlocations so as that the infrared light reflected may be entered intothe imaging apparatus of a person who is conducting the unauthorizedact) as well as the above-cited embodiments or the other embodiments.FIG. 9 show an configuration example of a case in which the presentinvention is applied to the first embodiment example.

[0225] Similar to the other embodiment examples, the present embodimentmay be applicable to a home theater as well as a movie theater or anyother theater system. Of course, the visual images projected onto thescreen include television programs and the other copyrighted products aswell as a movie. Next, a specific example of each apparatus composingthe system shown in FIG. 9 will now be described. Here, explanations areomitted except an emission control unit 7 since they are similar to thefirst embodiment example. The same applies to case where the presentembodiment is combined with the other embodiment examples.

[0226] The most simple emission control method is an emission pattern inwhich light-on and light-off are repeated in turn with a base cycle. Inthis case, the emission control unit 7 may be realized by, for example,an oscillator, a multi-vibrator, or any other oscillation means. In suchcase, the emission control unit 7 may also be constructed with acomputer, an IC for specific purpose, or any other logic circuits. Theintermittent emission of the infrared light can cause difficulties inthe viewing even the infrared light image is not bright in the recordedvisual image since the intermittently emitted infrared light is easierto be recognized. Of course, it is possible to deteriorate the visualimage that is imaged in the unauthorized manner as much as the viewingbecomes very difficult in case that brightness of the recorded lightimage is high since a change of the brightness level may be set tolarge.

[0227] In case that more complex control is required, it is necessary tohave a recording unit for an emission code (or emission pattern)indicating a predetermined information (for example output date, outputlocation, screen number or the like) to be recorded, and an output unitfor reading out an emission control information (light-on and light-off)signal according to the emission code from the recording unit to output.Of course, in order to automatically convert the emission code accordingto an arbitrary prescribed information inputted by a supervisor, it ispreferred to further include a conversion table or any other convertingmeans for converting the prescribed information to the emission code.

[0228] Further, as shown in FIG. 9, the emission control unit 7 may bean apparatus independent from the infrared light projector apparatus 3,or may be provided inside of the infrared light projector apparatus 3composing a single unit. In case that the emission control unit 7 isprovided inside of the infrared light projector apparatus 3 composingthe single unit and a plurality of the infrared light projectorapparatus 3 are used, synchronizations among these apparatus areadopted.

[0229] Next, the other emission control methods are described. A basicemission control method is dedicated for disabling the viewing ofrecorded visual images. However, a desired information may be recordedby controlling the intermittent emission itself. Of course, the emissioncontrol unit 7 controls the emission timing.

[0230] For example, as shown in FIG. 10, the desired information may beembedded along the time axis by assigning data “1” of binary code toLight-On and “0” to Light-Off in case that the emission code“10001110010” is indicating a movie theater ID of “001”. In FIG. 10, itmay be seen that 1 frame (1 field) is the minimum unit of the light-onand the light-off. However, the minimum unit required for indicatingsingle value of the emission code may be arbitrarily varied. Forexample, 0.5 second or 1 second may be used for the minimum unit. Incase that the unauthorized imaging act is performed, such light imagesare recorded so as to not only disable the viewing of the recordedvisual images but also identify a location where the unauthorizedimaging was taken place when such the recorded visual image is placed ina market. Although FIG. 10 shows a case in which single emission sourceis used, the emission control can be similarly performed with aplurality of the emission sources.

[0231]FIG. 11 shows another control method for embedding a desiredinformation along the time axis. In the above cited case of FIG. 10,recording position of the light image is fixed (namely, the emissionsource is fixed). However, it is possible to transit the recordingposition of the light image itself in a relay form as shown in FIG. 11.No meaning is provided in the recording position of the light image incase of FIG. 11. Also in this way, the same information as FIG. 11 maybe recorded.

[0232]FIG. 11 shows the emission pattern and its recording example for acase that four positions at four corners of the screen are assigned asrecording positions where the infrared light images are to be recordedand a rule is applied to advance the recording position of the lightimage in a clock wise direction every time the emission code valuechanges from “0” to “1”. Of course the other rules may be applied, too.For example, the following may be contemplated. The rule may include arule of advancing the recording position of the light image in aclockwise direction every time “1” is appeared in the emission code, arule of advancing the light image in a counter clockwise, a rule oftransiting the light image to a point other than the neighboring lightimage candidate point in accordance with a predetermined emissionposition transition rule, or the like.

[0233]FIG. 12 shows another control method for embedding a desiredinformation along the time axis direction. FIG. 12 shows a method forrealizing recording of the information by assigning “1” and “0” of theemission code to combination patterns in which a plurality of the lightimages are appeared. This is an example in which the appearance positionof the light image also has meaning. FIG. 12 shows an recording exampleof a case in which “0” of the emission code is assigned to a combinationpattern in which two of the light images are appeared in the upper leftcorner and the lower right corner respectively, and “1” of the emissioncode is assigned to a combination pattern in which the light images isappeared only in the upper left corner. With using the control method,it is possible to identify the location where the unauthorized act wasperformed. Of course, the positions at which the infrared light image isrecorded may be positions other than the four corners of the screen, andthe combination patterns indicating each code vale may use the otherones. For example, in the above cited case, “1” of the emission code maybe assigned to a combination pattern in which two of the light imagesare appeared in the upper right corner and the lower left cornerrespectively.

[0234]FIG. 13 shows an modification example of FIG. 12. In the case ofFIG. 12, “0” and “1” of the emission code are assigned to thecombination patterns of the light image. However, in this example, onlysingle light image is assigned. That is, meaning is provided on theappearing position. In FIG. 13, “0” of the emission code corresponds tothe light image appeared at the upper left corner of the screen, “1” ofthe emission code corresponds to the light image appeared at the lowerright corner of the screen. As to the synchronized control of emissiontiming oftwo light images, FIG. 13 is one of the controller of FIG. 12.

[0235] Examples described in the above are the cases where each of thelight image patterns appeared along the time axis direction has ownmeaning. However, the following method may be contemplated, too. Thatis, the method is to superpose information on the light image patternitself. For example, as shown in FIG. 14, the following case may becontemplated. In such case, only a pattern of the light image positionsappeared in a predetermined time period has meaning and no meaning isattached to the transition of the light image appearance position northeir appearance order when the appearance position of the light imagetransits as time elapse. That is, FIG. 14 shows a case in which thelight image appearance position is transited “upper left corner→lowerright corner→upper left corner→lower left corner→upper left corner→lowerright corner” whereby providing meaning to a light image pattern itselfrecognized at a plane independent of the time axis (time axiscompressed). Here, the predetermined information is indicated by lightimage patterns appeared at corners excluding the upper right corner. Theemission control method intending such superposition of the informationmay also be contemplated. It is possible to contemplate an emissioncontrol method intending to use such information superposition.Alternatively, the emission may be controlled so as that the lightimages appear at three points except the upper right cornersimultaneously.

[0236] It becomes possible to record the predetermined information inaddition to disabling the viewing by performing the intermittentemission control of the infrared light like the present embodimentexample, namely by intermittently projecting the infrared light image(spot light) on the screen. Further, in case that the information issuperposed on the intermittent emission itself, the light image itselfmay be recognized independent of the main feature program content or thebrightness since a large spot light that is easily recognizable may beused. On the other hand, in case that character information is recordedby focusing the infrared light on the screen like the conventionalsystem, there may be some difficulties in reading out the characterinformation depending on the main feature program content or thebrightness.

[0237] In the explanation described above, it is basically assumed thatsingle information is to be recorded (in this case the same pattern isrepeatedly appeared with a predetermined interval). However, in casethat a plurality of information are to be recorded, a control may beperformed so as to project light image patterns corresponding to thedifferent information with a predetermined interval.

(6) SIXTH EMBODIMENT EXAMPLE

[0238] The sixth embodiment example is shown in FIG. 15. This embodimentexample is related to a novel feature of projecting the infrared lightonto the screen during scenes of the low brightness or for selectivelyprojecting the infrared light onto screen surface areas having lowbrightness whereby increasing the prevention effect with the infraredlight. This embodiment may be applicable to a conventional system(system in which the infrared light is projected to the screen 2 from avicinity of the projector apparatus or any other distant locations so asthat the infrared light reflected is entered into the imaging apparatusof a person who is conducting the unauthorized act) as well as theabove-cited embodiments or the other embodiments.

[0239]FIG. 15 shows an application example of a movie theater or anyother theater system. However, like the other embodiment examples, thetechnique itself may be applicable to a home theater. Of course, thevisual images projected onto the screen include television programs andthe other copyrighted products as well as a movie.

[0240] Next, a specific example of each apparatus composing the systemshown in FIG. 15 will now be described. The system shown in FIG. 15 isto dispose the infrared light projector apparatus 3 at the rear side ofthe screen like the system related to the first embodiment example. Asto this point, the present embodiment example is one example of thefirst embodiment example. The same projector apparatus 1 and the samescreen 2 are used as the first embodiment example. Of course, the sameinfrared light projector apparatus 3 is used as the first embodimentexample. That is, the infrared light projector apparatus 3 may bedisposed not only the rear side of the screen but also disposed in thefront side or a vicinity of the screen.

[0241] However, in the present embodiment example, a plurality of theinfrared light projector apparatus 3 are provided at least as much asthe number of virtual areas assumed so as to selectively project theinfrared light onto areas on the screen having low brightness. Here, atleast 28 of the infrared light projector apparatus 3 are required sinceit is assumed that the screen surface is virtually divided into 28partial areas (4 lines×7 rows). In the present embodiment, the samenumber of the light sensors as the number of virtual areas, namely, 28light sensors are provided. A proper value is determined for the numberof the partial areas for each system by considering a size of the screen2, a size or disposition method of the infrared light projectorapparatus 3, or any other conditions.

[0242] The light sensor 8 is means for detecting correspondingbrightness of the screen 2 based on the projection light transmitting orpassing through the screen 2. As the light sensor, a photodiode or aphototransistor may be used, for example. The light sensor 8 is disposedat the rear side of the screen 2. A distance from the screen 2 to theposition, at where the light sensor 8 is disposed, may differ dependingon a size of the partial area corresponding to each sensor 8. Forexample, the sensor 8 has to be disposed closely to the rear sidesurface of the screen 2 so as to detect the brightness at thecorresponding area precisely if the partial area has smaller size whilethe sensor 8 may be separated with some distance from the screen 2 ifthe partial area has larger size.

[0243] In a typical case, the light sensor 8 is disposed at a vicinityof the center of the corresponding partial area. This is because that adetection value of the light sensor 8 becomes a representative value ofthe brightness at each partial area. However, it is not necessary to bethe exact center of the partial area. In case a plurality of the lightsensors 8 are used for detecting brightness of single partial area, thelight sensor may not be provided at the center of each partial area.

[0244] The infrared light projector apparatus 3 or the light sensor 8described above may be disposed relatively arbitral position when aspeaker is not provided in the rear side of the screen. However, whenthe speaker is disposed at the rear side of the screen, the infraredlight projector apparatus 3 or the light sensor 8 has to be disposed soas not to interfere the replay operation.

[0245] The infrared light projector apparatus 3 and the light sensor 8described above may be disposed separately as independent apparatus, ormay be disposed as an emission unit in an integral body as shown in FIG.16. In a case of FIG. 16, the infrared light projector apparatus 3 is anunit apparatus in which a plurality of the infrared light emittingdevices 3A (here, six units) are arrayed in a single plane. The lightsensor 8 is disposed at a vicinity of the center of the infrared lightprojector apparatus 3. Such infrared light projector apparatus 3 may bedisposed at each partial area of FIG. 15.

[0246] Further, the light sensor 8 outputs detection signals (forexample, current value, voltage value) S2 in accordance with thecorresponding screen brightness. Such detection signal may be an analogsignal or digital signal. In a case of FIG. 16, a control signal S3controlling the emission of the infrared light emitting device 3A issent to the infrared light projector apparatus 3 from the infrared lightprojector control apparatus 10.

[0247] The shutter sensor 9 is an effective device in case that theprojector apparatus 1 is a film-type projector apparatus. Accordingly,in case that a digital signal type projector is employed for theprojector apparatus 1, such shutter sensor 9 does not exist in itsconfiguration. Here, the shutter sensor 9 is used so as to project theinfrared light on the screen during periods in which a shutter of thefilm-type projector apparatus (so-called a cinema projector) shields theprojection light. That is, the shutter sensor 9 is used for detectingthe periods or timings during which the shutter is closed and the screenbrightness is decreased.

[0248]FIG. 17 shows a representative configuration example of thepresent function. The cinema projector projects visual images on thescreen by repeating an operation of projecting the visual images ontothe screen by radiating a light-source light 12 when a film 11 staysstill at an aperture (film projection window of the projector) and anoperation of shielding the light-source light 12 radiated on the film 11to transfer the frames during the shielding period. A lens 14 in thisfigure is a projection lens to project the light-source light to thescreen 2.

[0249] In general, a circular plate having cut sections is employed asthe shutter 13 used for shielding the light-source light. Typically,these cut sections may be provided at two position at opposing angles ofthe circular plate. Typically, the circular plate rotates 24 times persecond, and shields the light-source light twice in every one frame(FIG. 18(B)). An inter-sprocket 15 transfers the film 11 for one frameduring one of two shielding periods which appear twice per frame toshield the light-source light (FIG. 18(A)). The infrared light projectorapparatus 3 coupled with the motion timing of the shutter 13 projectsthe infrared light twice per frame (FIG. 18(C)).

[0250] As the shutter sensor 9, not only an optical type but also anelectronic or mechanical type may be contemplated. For example, as theoptical type, a method shown in FIG. 19 may be contemplated. FIG. 19 isthe method for determining a positional relationship (rotationalposition) in which the shutter 13 shields the light-source light bydetecting light flux reflected at the shutter surface. FIG. 19(A) showsa state in which the light-source light 12 is projected, 19(B) shows astate in which shielding of the shutter 13 is started, FIG. 19(C) showsa state in which the shutter 13 is shielding light-source light 12.

[0251] In case that the method of FIG. 19 is used, the shutter sensor 9may be disposed so as that the shutter 13 is faced with a vane duringthe shielding of the light. As the shutter sensor 9, a light emittingdiode (emission means) and a photo diode (light reception means)disposed at a plane facing the shutter 13 may be used. According to thisconfiguration, the positional relationship of the shutter may bedetected since an amount of light received by the photodiode is highduring the shielding of the light-source light and the amount of lightis low during the projection.

[0252] As the optical type method, there is a method for detecting thepositional relationship (rotational position) of the shutter 13 bydisposing the light emitting diode and the photodiode so as to face eachother sandwiching the circular plate's rotation area and determiningwhether the light emitted from the light emitting diode is detected bythe photodiode. In this case, the rotational position of the circularplate may be detected based on a light receiving timing and a lightshielding timing of the light emitted to the photodiode from the lightemitting diode.

[0253] Alternatively, a method for mechanically detecting a rotationalposition of the circular plate may be employed for the shutter sensor 9.For example, it is possible to mechanically detect the shutter'srotational position from a rotational position (position of gear) of agear attached to a rotational axis so as to have the same axis. Further,for example, the following method may be contemplated. The method is fordetecting whether the cut section or the circular plate's vane ispositioned from a change in an electrostatic capacitance betweenelectrodes disposed so as to sandwich the rotational area of thecircular plate. Further, a method for detecting the shutter's rotationalposition from a drive information itself of the rotational axis.

[0254] Of course, the shutter sensor 9 in accordance with a form or atype of the shutter may be employed in case that the form or the type ofthe shutter may differ. For example, in case that open-close of theshutter is electronically controlled, it is possible to use a method fordetecting a period of the light-source light shielding using theopen-close signal.

[0255] The following methods may be contemplated as an utilizing methodof the detection results. The methods includes a method for emitting theinfrared light when the shutter's close motion is detected and a methodfor forecasting the shutter's close motion from the detection result andemitting the infrared light at a forecasted timing.

[0256] The infrared light projector control apparatus 10 is a mean forcontrolling the emission of the infrared light projector apparatus 3(each infrared light emitting device 3A in the configuration of FIG. 16)according to a light sensor output S2 outputted from the light sensor 8or a shutter information S4 outputted from the shutter sensor 9.

[0257] An internal configuration of the infrared light projector controlapparatus 10 may differ depending of a system to which the infraredlight projector control apparatus 10 is to be applied. For example, acomputer (having a processing unit (having a controller and an operationdevice), a memory, an input/output unit) is generally used in case thatthe system has a configuration for simultaneously controlling all of theinfrared light projector apparatus 3 as shown in FIG. 15. However, it isalso possible to realize functions of programs executed by the computeras electronic circuits.

[0258] However, the infrared light projector control apparatus 10 maynot be required for every case. For example, a desired prevention effectmay be realized without using the control apparatus by directly usingdetection results of the light sensor 8 as a light amount adjustingsignal for the infrared light projector apparatus 3 to increase anamount of the infrared light in a scene or area in which the screen isdark. Here, it is assumed that the detection result changes in analogform. Alternatively, a multi-valued information may be outputted as thelight amount adjusting signal in case that the light sensor has afunction of converting the analog signal to the digital signal.

[0259] For example, it is possible to configure a system capable ofswitching the infrared light projection and non-projection by directlyinputting the detection results of the light sensor 8 into the infraredlight projector apparatus 3 in case that the light sensor 8 has afunction of determining whether the screen brightness is brighter than apredetermined reference value or not (in case that it has a comparisonfunction of comparing the detection results and the predeterminedreference value). Of course, the infrared light is projected in casethat the screen brightness is equal or less than the predeterminedreference value.

[0260] For example, a desired prevention effect may be realized withoutusing the control apparatus by using the detection result of the shuttersensor 9 as an on-off control signal of the infrared light projectorapparatus 3 and projecting the infrared light at a time of the frametransfer at which the screen becomes dark.

[0261] An explanation comes back to a case in which the infrared lightprojector control apparatus 10 is used. For example, the infrared lightprojector control apparatus 10 commands the infrared light projectorapparatus 3 to project the infrared light by outputting the controlsignal S3 when the shutter's close motion (namely the infrared light isshielded) is detected by the shutter sensor 9. Here, the infrared lightprojector control apparatus 10 may command all of the infrared lightprojector apparatus (in case of FIG. 15, it is possible to command all28 units of the infrared light projector apparatus to project).Alternatively, the infrared light projector control apparatus 10 maycommand a part of the infrared light projector apparatus to project theinfrared light. For example, in case of FIG. 15, it may command theprojection of the infrared light so as that the emission pattern becomesa check pattern. Alternatively, it is also possible to command theprojection of the infrared light so as that the emission pattern formsan other recognizable graphic pattern (may include character ornotation).

[0262] In case that the infrared light projector control apparatus 10 isconfigured as a group of plural infrared light emitting devices as shownin FIG. 16 and the projection command of the infrared light is sent tothe infrared light projector control apparatus 10, there may be a casethat the emission is ordered to all of the infrared light emittingdevices as shown in FIG. 20(A), and a case that the emission is orderedto a part of the infrared light emitting devices as shown in FIG. 20(B).A more complex graphic pattern may be recorded by combining the otheremission pattern of the neighboring infrared light projection apparatus10 by controlling the emission of the infrared light emitting devices asshown in FIG. 20(B).

[0263] Next, a control operation example will now be explained for acase that the detection result of the light sensor 8 is inputted intothe infrared light projector control apparatus 10. The most simplecontrol method is a method for judging the screen brightness based onthe detection output of the light sensor 8 and emission-controlling theinfrared light projector apparatus 3 assigned to an area to be monitoredby the light sensor when the brightness is a lower than thepredetermined brightness. Of course such control function may berealized by means of software or hardware.

[0264] In case that the judgment process is executed in digital manner,the infrared light projector control apparatus 10 may be constructed tohave a memory (memory means) for recording a threshold value to be acomparison reference value, a comparator (comparison means) forcomparing an input value (value converted by means of converting to adigital signal in case outputs of the light sensor is the analog signal)and the above-cited threshold value, and an output unit (output means)for outputting the comparison result to corresponding infrared lightprojection apparatus 3. On the other hand, in case that the judgmentprocess is executed in analog manner, the infrared light projectorcontrol apparatus 10 may be constructed to have a comparison circuitstage of a differential amplifier circuit configuration for comparingthe light sensor input and a reference value (for example, generated byresistance divided voltage), and an output stage for outputting thedifferential output.

[0265] Here, the threshold value may be determined, for example, basedon measured values or empirical values with consideration of recordingcharacteristics of the imaging apparatus (for example, opticalcharacteristic of a solid state imaging apparatus) or visual sensecharacteristic of human being. In case that a disposition density of thelight sensor is relatively high, the infrared light emission does notbring much effect at the low brightness region when an output from aspecific light sensor indicates relatively low brightness while anoutput from the other light sensors in the vicinity indicate highbrightness. Accordingly, it is possible to control not to emit theinfrared light when such condition is satisfied.

[0266] Even in case that the infrared light is selectively projected onto the screen areas having the low brightness, the following method maybe contemplated. The method is for emitting only a part of the infraredlight emitting devices corresponding to the area as shown in FIG. 20(B).In this case, a memory for recording a predetermined emission patternand program steps for generating the emission pattern are added to theprevious configuration.

[0267] The control operation described above is an operation example fora case that only one light sensor 8 is basically disposed in an area inwhich the infrared light is to be projected. However, the followingoperation method may be employed in case that a plurality of the lightsensors are disposed in the area in which the infrared light is to beprojected. The area in which the infrared light is to be projected maybe each of the partial areas of FIG. 15, or may be a plurality of thepartial areas (Maximum is a whole area of the screen).

[0268] In the following, an explanation is given in case that the wholearea of the screen is considered to be the infrared light projectionarea since the control operations themselves are the same. That is, itwill now be explained how 28 detection results are used to generate aprojection command of the infrared light as shown in FIG. 15.

[0269] For example, there is a method for using the number of the lightsensors 8, by which the low screen brightness are detected, as ajudgment reference. The same methods described above may be applieddirectly here for judging whether the brightness is low or not.

[0270] In this case, the infrared light projector control apparatus 10compares the predetermined threshold value stored in the memory and thedetected value counted at every time-point counted by a counter (thenumber of the light sensors judged as the low brightness) with thecomparator, and issues the emission command to project the infraredlight on the whole screen which is the area to be projected when thedetected value is bigger than the predetermined threshold value. In casethat a predetermined pattern is to be formed from a plurality of lightimages, the infrared light projector control apparatus 10 issues theemission command only to the infrared light projection apparatuscorresponding to the pattern. In this case, the infrared light projectorcontrol apparatus 10 identifies positional information of the infraredlight projection apparatus corresponding to a predetermined pattern byreading out the recording apparatus, or identifies positionalinformation of the infrared light projection apparatus corresponding toa predetermined pattern by calculation.

[0271] Regarding to the judgment reference, there is a method for usinga position of the light sensor 8 that detected the low screenbrightness. For example, there is a method for using the output of thelight sensor 8 disposed in a vicinity of the screen center as an objectto be judged. There is an advantage of ascertain the recording of theinfrared light at the center part of the screen since a vicinity of thescreen center is visually a highly visible part. Alternatively, there isa method for using the output of the light sensor 8 disposed in avicinity of the screen surrounding (for example, screen's outerperiphery, one of four corners, all of four corners, or the like) as anobject to be judged. Although the prevention effect may be limited atthe screen surrounding compared to the center part, a certain preventioneffect may be anticipated since the rest of the area (including thescreen center) is often also dark when the surrounding to be judged isdark. Further, ample prevention effect may be realized by letting theinfrared light images appear very often even the appearance position isat the surrounding.

[0272] Further, for example, the following method or the like may becontemplated. The method is for using the output of the light sensor 8disposed at a plurality of judgment points set up on the screen (forexample, five points comprising four corners of the screen and thecenter part) as objects to be judged. Although it depends on the numberof the measurement points and a set-up method, the infrared light may beprojected at least on the dark area of the screen. In case of fixing thejudgment point as described above, the light sensors 8 may be disposedonly at these judgment points.

[0273] In the above described example, the emission of the infraredlight is basically controlled by judging whether the low brightness isdetected at the judgment area or point. However, in case that aplurality of the light sensors 8 are disposed at single judgment area orpoint, the judgment of the low output may be performed regarding to thejudgment area or point only when the number of the light sensors, fromwhich the judgment of the low brightness is obtained, is larger than apredetermined number.

[0274] In the above described example, the detection results regardingthe judgment points are used as judgment elements. However, the judgmenton whether the infrared light should be projected or not may beperformed based on a distribution pattern of the light sensors in whichthe judgment result of the low brightness is obtained while using allthe light sensors disposed at the rear side of the screen as thejudgment elements. In this case, there are provided a distributionpattern for triggering the infrared light projection and a distributionpattern for not triggering the infrared light projection, or, one ofthose distribution patterns. And the judgment of whether the infraredlight is projected or not may also be performed according to a degree ofcoincidence with the distribution pattern.

[0275] The infrared light projector control apparatus in this case mayfurther comprises a memory for recording the distribution pattern forthe judgment, a distribution pattern recording an actual measurementdistribution pattern of the light sensors in which the detection resultof the low brightness is obtained, and a judgment unit for judging thedegree of coincidence between these.

[0276] Of course, in case that the infrared light projection isperformed as a result of the judgment, the above cited techniques may beapplicable to operations for forming a predetermined pattern from the aplurality of the light images.

[0277] As in the present embodiment example, it is possible to ascertainthe recording of the infrared light into the imaging apparatus of aperson conducting the unauthorized act by selectively projecting theinfrared light onto scenes or areas in which the screen brightness islow since the infrared light is projected onto the scenes or areas inwhich the brightness of the infrared light images becomes certainlyhigher than the visual images of the main feature program. Particularly,in case that the area to which the individual light image is projectedis limited to a relatively small area as shown in FIG. 15, an outputlevel may be a small value in the infrared light projector apparatusitself since the brightness of the light image on the screen may beincreased as much as the spreading of the light flux is tightened.

[0278] Further, it is possible to prolong the product life time and thepower consumption since the infrared light is emitted only in the sceneor area in which the prevention effect is discernible.

(7) SEVENTH EMBODIMENT EXAMPLE

[0279] The seventh embodiment example is shown in FIG. 21. Thisembodiment example is a modification example of the sixth embodimentexample. Accordingly, the same applies to points of projecting theinfrared light onto the scene in which the screen brightness is low orselectively projecting to the area of the screen surface in whichbrightness is low, in order to increase the prevention effect of theinfrared light.

[0280] However, the present embodiment example and the sixth embodimentexample are different in a method for acquiring information regardingthe scene or time-point in which the screen brightness decreases. Thatis, the present embodiment example differs from the sixth embodimentexample on a point of acquiring information of time-point in which anaverage brightness of the screen decreases (time information) orinformation regarding partial area and time-point in which the screenbrightness decreases (namely, position information and timeinformation), from a recording medium or via a network.

[0281] Accordingly, no light sensor is required in the presentembodiment example. The basic configuration is the same as the sixthembodiment example. Accordingly, the screen configuration and thedisposition of the infrared light projector apparatus are similar to thesixth embodiment example. Although the infrared light projectorapparatus 3 is disposed in the rear side of the screen 2, the projectionmay also be done from the front side of the screen 2.

[0282] A program server 16 is an apparatus to output visual image dataS5 to the projector apparatus 1. Here, there may be cases that thevisual image data S5 is data read out from a recording medium 17 (forexample, video tape, CD-ROM, DVD or the like) or that the visual imagedata S5 is data being distributed via a network 18. However, such visualimage data S5 is not outputted in case that the projector apparatus 1 isa film type projector apparatus.

[0283] The program server 16 also functions as an apparatus replayingthe time information or the position information of the partial areasuited for projecting the infrared light from the recording medium 17,or receiving those information via the network 18. That is, the programserver 16 also functions as an apparatus outputting an infrared lightprojection control data S6 to the infrared light projector controlapparatus 10. The recording medium may be one provided through a mailservice or a package delivery service, or one recording data distributedvia the network 18 in advance.

[0284] Here, a synchronization between the visual image data S5 to beoutputted to the projector apparatus 1 and the infrared light projectioncontrol data S6 to be outputted to the infrared light projector controlapparatus 10 is performed by the program server 16. Of course, in casethat the digital type projection system as shown in FIG. 21, thesynchronization between data is controlled based on the commonsynchronization information or the time information for reproduction. Incase that the projector apparatus 1 is the film type, an output timingof the infrared light projection control data S6 is controlled based onthe synchronization signal or the position information read out from thefilm, or the rotational position information of the shutter 13.

[0285] The following cases may be contemplated for the infrared lightprojection control signal S6. The case may be a case in which theinfrared light projection control signal S6 includes only the time-pointinformation wherein the screen brightness decreases (time information),a case in which the infrared light projection control signal S6 includesthe partial area and the time-point information wherein the screenbrightness decreases (namely, position information and timeinformation), or a case combining these cases.

[0286] For example, in case the projector apparatus 1 is a digital typeapparatus, it is possible to contemplate that the infrared lightprojection control data S6 may be information of a time-point in whichthe light-source light is shielded with the shutter 13, information of apre-detected time-point in which an average screen brightness decreases(depending on contents of the visual images), information of apre-detected time-point in which the screen brightness decreasespartially (depending on contents of the visual images).

[0287] Alternatively, in case the projector apparatus 1 is a digitaltype apparatus, it is possible to contemplate that the infrared lightprojection control data S6 may be information of a pre-detectedtime-point in which an average screen brightness decreases (depending oncontents of the visual images), information of a pre-detected time-pointin which the screen brightness decreases partially (depending oncontents of the visual images).

[0288] The infrared light projector control apparatus 10 is means forspecifically controlling the emission of the infrared light projectorapparatus 3 in practice. As similar to the sixth embodiment example, theinfrared light projector control apparatus 10 may command all of theinfrared light projector apparatus 3 to project the infrared light, or,may command only a part of the infrared light projector apparatus 3 toproject the infrared light. Of course, in case the infrared lightprojector apparatus 3 is configured as a group of plural infrared lightemitting devices as shown in FIG. 16, all of the plural infrared lightemitting devices may be emitted, or, only a part of them may becontrolled to emitted.

[0289] Also in the present embodiment example, it is possible toascertain the recording of the infrared light into the imaging apparatusof a person conducting the unauthorized act by selectively projectingthe infrared light onto scenes or areas in which the screen brightnessis low since the infrared light is projected onto the scenes or areas inwhich the brightness of the infrared light images becomes certainlyhigher than the visual images of the main feature program. Particularly,in case that the area to which the individual light image is projectedis limited to a relatively small area as shown in FIG. 21, an outputlevel may be a small value in the infrared light projector apparatusitself since the brightness of the light image on the screen may beincreased as much as the spreading of the light flux is tightened.

[0290] Further, it is possible to prolong the product life time and thepower consumption since the infrared light is emitted only in the sceneor area in which the prevention effect is discernible.

(8) EIGHTH EMBODIMENT EXAMPLE

[0291] The eighth embodiment example is shown in FIG. 22. Thisembodiment example relates to a novel feature of increasing the amountof the infrared light reflected at the screen surface to an value morethan that of an conventional system by disposing the infrared lightprojector apparatus 3 at a vicinity position in the front side of thescreen and projecting the infrared light to the screen from the infraredlight projector apparatus 3.

[0292]FIG. 22 represents a composite system comprising the presentembodiment and the above described sixth embodiment example (the novelfeature of controlling the emission timing of the infrared light base onthe shutter information) or the above described seventh embodimentexample (the novel feature of controlling the emission timing of theinfrared light base on the infrared light projection control data).

[0293] Further, the present embodiment example is an application exampleof a novel feature of automatically adjusting the infrared lightprojecting direction in accordance with a change of the screen sizedepending on the contents.

[0294]FIG. 22 also shows an example applicable for a movie theater orother theater systems. Of course, as similar to the other embodimentexamples, the technique itself may be applicable to a home theater. Inany cases, the visual images projected onto the screen includetelevision programs and the other copyrighted products as well as amovie.

[0295] First, a disposition method of the infrared light projectorapparatus 3, that is unique for the present embodiment example, may beexplained. For example, as shown in FIG. 22, the infrared lightprojector apparatus 3 is disposed somewhat front side of the screenperiphery part (for example, screen frame or outer border area). In thiscase, the infrared light is projected within a range from an angle closeto the horizontal direction to an angle close to the vertical directiondepending on a projection position on the screen surface, and theinfrared light randomly reflected on the screen or the like incidentinto the imaging apparatus of a person conducting the unauthorized act.The incident angle of the infrared light is determined according to asize of the screen 2 or the disposition location of the infrared lightprojector apparatus 3, and not limited to any particular ranges.

[0296]FIG. 22 shows eight units of the infrared light projectorapparatus 3 disposed along the top and the bottom rims for the longerrims (transversal direction) and five units of the infrared lightprojector apparatus 3 disposed along the right and the left rims for theshorter rims (vertical direction). However, the infrared light projectorapparatus 3 may be disposed along only one of the rims, or the infraredlight projector apparatus 3 may be disposed along any two arbitraryrims, or the infrared light projector apparatus 3 may be disposed alongany three arbitrary rims. Of course, any arbitrary number of theinfrared light projector apparatus 3 may be disposed.

[0297] In case that the infrared light projector apparatus 3 is disposedin a vicinity of the screen 2, the infrared light projector apparatus 3may be disposed at not only the screen periphery part but also a pointcloser to the screen than the midpoint of the projector apparatus 1 andthe screen 2. For example, the disposition location of the infraredlight projector apparatus 3 may be at L/3, L/4, L/5 from the screenwhere L is a distance between the projector apparatus and the screen.

[0298] Next, characteristic apparatus among the system shown in FIG. 22will now be explained. Explanations of the other apparatus examples areomitted since those are common to the other embodiment examples. Thereare two characteristic apparatus. Those are a projector directingactuator apparatus 19 and a screen mask switching apparatus 20. Thoseare apparatus for auto-adjusting a projection position or direction ofthe infrared light automatically coupled to the switching of the screensize in case that there are a plurality of the screen sizes suited forthe projected visual images.

[0299]FIG. 23 shows an attachment example of the infrared lightprojector apparatus 3 to the projector directing actuator apparatus 19.FIG. 23 represents a state in which the projector directing actuatorapparatus 19 is turnably attached on the backside of the infrared lightprojector apparatus 3 (opposite side to the infrared light projectingdirection). Here, the turning axis is orthogonal to the optical axis.The infrared light projector apparatus 3 is coupled to the projectordirecting actuator apparatus 19 through a motor and a gear, and attachedso as to turn a predetermined angle in a predetermined direction inaccordance with an amount of the motor rotation.

[0300] The actuator apparatus is not limited to a technique transferringpower by an amount of rotation but also one transferring the power withan amount of linear motion. Further, the infrared light projectorapparatus 3 may be an object to be directly driven by the actuatorapparatus, or may be an object to be indirectly driven through a gear orrubber or any other coupling devices by the actuator apparatus. In caseof FIG. 23, the moving direction is only one. However, it may beconstructed to have two movable directions. For example, it may have twomovable directions, the horizontal direction and the vertical direction.

[0301] The screen mask switching apparatus 20 is means for automaticallyproviding an actuator control information of the infrared lightprojector apparatus to the projector directing actuator apparatus 19according to a command of the screen size switching. For example, thescreen mask switching apparatus 20 comprises a memory unit for recordingscreen sizes and information regarding a projecting direction of eachinfrared light projector apparatus suited for the corresponding screensize (for example, information regarding projecting direction or angle),and a control unit reading out a numerical value suited for the screensize after the switching from the memory unit and outputting thenumerical value to each position of the projector directing actuatorapparatus 19. Alternatively, the information to be outputted to theprojector directing actuator apparatus 19 may be provided by calculatingan adjusting amount with respect to the current value (differentiationvalue) in case that a target value (optimum value) itself is notprovided like the present example. One of these data may be outputted asa control data S7 from the screen mask switching apparatus 20 to theprojector directing actuator apparatus 19.

[0302] The switching command of the screen size or the optimum screensize information may be provided in conjunction with a manual operationof an operator in one case, or may be automatically provided based oninformation recorded in association with a visual image content in theother case. For example, in case of a movie theater, a person in chargeat the theater side operates a button to change a position of a blackoutcurtain (mask) when the screen size (aspect ratio) is switched. Suchbutton operation may be shared for switching the projecting direction.In case the recorded information is used as in the latter case, it ispossible to contemplate a case in which the optimum information isrecorded in a medium recording the visual image contents, and the othercase in which a corresponding chart is recorded in the other recordingmedium separated from the visual image contents.

[0303] Although FIG. 22 shows the projector directing actuator apparatus19 and the screen mask switching apparatus 20 as separated apparatus,these may be constructed as single apparatus. Further, the adjustment ofthe infrared light projecting direction may be done not only forindividual infrared light projector apparatus but also for a row unit ora unit of neighboring plural infrared light projector apparatus.

[0304] It is possible to further increase the prevention effect againstthe unauthorized imaging act since an amount of the reflection light maybe increased remarkably in comparison with an conventional system byprojecting the infrared light to the screen from the vicinity positionof the screen so as that the reflected light may be incident into theimaging apparatus of a person conducting the unauthorized act, as in thepresent embodiment example. Further, an effect of deteriorating thequality of visual images imaged in the unauthorized manner may bepromoted by combining the technique of selectively projecting theinfrared light onto the scene where the screen brightness decreases orthe area of the low brightness. Of course, it is possible to ascertainthe recording of a desired information by combining the intermittentprojection or the selectively projection techniques at a time ofinfrared light projection.

[0305] Further, it is possible to effectively avoid an event in whichthe infrared light is projected at outside of the visual image contentprojecting area by automatically adjusting the infrared light projectingdirection according to the screen size, as in the present embodimentexample. Namely, it is possible to increase the prevention effect bymost effectively utilizing the available infrared light projectorapparatus.

[0306] In the above, the explanation is given to a composite systemcomprising a portion projecting the infrared light from the front sidevicinity of the screen, a portion relating the automatic adjustmentfunction of the projecting direction, and a portion relating toselective projection technique at the low brightness area or scene.However, it is possible to contemplate a system configuration includingonly the portion projecting the infrared light from the front sidevicinity of the screen, or a system configuration including only theportion relating to the automatic adjusting function of the projectingdirection.

(9) NINTH EMBODIMENT EXAMPLE

[0307] In each of the above described embodiments, representativeexamples are described for the specific examples of the conceptualembodiment examples. However, it is possible to contemplate variousembodiment examples such as composite systems of the above describedembodiment examples or modification examples or the like.

[0308] According to the embodiments according to the present inventiondescribed in the present specification, the following effects may berealized.

[0309] (A) It is possible to have projected infrared light effectivelyincident into imaging apparatus of a person conducting the unauthorizedact since infrared light is projected to a viewer/audience directionfrom one or more infrared light projector apparatus disposed at a screenside to allow the infrared light incident into the imaging apparatus ofa person conducting the unauthorized act. Accordingly, the embodimentmay produce ample prevention effect even when the low power infraredlight projector apparatus is used.

[0310] (B) It is possible to have projected infrared light effectivelyincident into imaging apparatus of a person conducting the unauthorizedact since infrared light is actively reflected by an infrared lightreflection mirror so as that the reflected infrared light incident intoimaging apparatus of a person conducting the unauthorized act.Accordingly, the embodiment may produce ample prevention effect evenwhen the low power infrared light projector apparatus is used.

[0311] (C) Following effects may be realized by intermittently emittinginfrared light. For example, a location in which the unauthorized actwas taken place may be identified from the image obtained through theunauthorized manner by outputting the infrared light in accordance witha predetermined information. For another example, the viewing may becomevery difficult due to rapid change of brightness level by frequentlychanging emission intensity of infrared light.

[0312] (D) Prevention effect may be intensified further by selectivelyprojecting onto a part of the screen surface, in which brightness islower (for example, area or time period having a brightness of thescreen surface equal or less than a predetermined value) wherebyincreasing relative effects of the infrared light. Further, in case thatcertain information is superposed on the infrared light, suchinformation may be surely recorded.

[0313] (E) Prevention effect may be intensified further by projectinginfrared light to the screen from at least one or more infrared lightprojector apparatus disposed in the vicinity of the screen wherebysignificantly increasing an amount of infrared light reflected on thescreen, which may be incident into imaging apparatus of a personconducting the unauthorized act.

[0314] While the present invention has been particularly shown anddescribed with reference to the embodiments according to the presentinvention, it will be understood by those skilled in the art thatcombination of the embodiments and/or other changes in form and detailscan be made therein without departing from the essential characterthereof.

What is claimed is:
 1. An imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: projecting infrared light to aviewer/audience direction from at least one or more infrared lightprojector means, said at least one or more infrared light projectormeans being disposed at a rear side of the screen, whereby enabling saidinfrared light to be incident into imaging means of a person conductingthe unauthorized act.
 2. The imaging prevention method according toclaim 1, further comprising: letting at least a part of the infraredlight pass through space besides the screen so as said part of theinfrared light to be directly incident into said imaging means of aperson conducting the unauthorized act.
 3. The imaging prevention methodaccording to claim 1, further comprising: transmitting at least a partof the infrared light through the screen so as said part of the infraredlight to be incident into said imaging means of a person conducting theunauthorized act.
 4. The imaging prevention method according to claim 1,further comprising: letting at least a part of the infrared light passthrough a pass-through part provided in the screen so as said part ofthe infrared light to be incident directly into said imaging means of aperson conducting the unauthorized act.
 5. A imaging prevention methodfor interfering unauthorized imaging of visual image projected on ascreen, the imaging prevention method comprising: directly projectinginfrared light to a viewer/audience side from at least one or moreinfrared light projector means, said at least one or more infrared lightprojector means being disposed at a front side of the screen viewingfrom the viewer/audience side, whereby enabling said infrared light tobe directly incident into imaging means of a person conducting theunauthorized act.
 6. A imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: directly projecting infrared light to aviewer/audience side from at least one or more infrared light projectormeans, said at least one or more infrared light projector means beingdisposed in a vicinity of the screen, whereby enabling said infraredlight to be directly incident into imaging means of a person conductingthe unauthorized act.
 7. A imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: reflecting infrared light by infraredreflection means to a viewer/audience side, whereby enabling saidinfrared light to be directly incident into imaging means of a personconducting the unauthorized act, said infrared light being projectedfrom at least one or more infrared light projector means.
 8. The imagingprevention method according to claim 7, further comprising: driving saidinfrared light reflection means with actuator means to variably controla reflection direction whereby scanning the viewer/audience side withreflection light reflected by said infrared light reflection means.
 9. Aimaging prevention method for interfering unauthorized imaging of visualimage projected on a screen, further comprising: intermittently emittinginfrared light from at least one or more infrared light projector means,whereby enabling a predetermined intermittent emission pattern to berecorded in imaging means of a person conducting the unauthorized act.10. A imaging prevention method for interfering unauthorized imaging ofvisual image projected on a screen, further comprising: intermittentlyemitting infrared light from at least one or more infrared lightprojector means in accordance with a predetermined code information,whereby enabling information along a time axis direction to be recordedin imaging means of a person conducting the unauthorized act.
 11. Aimaging prevention method for interfering unauthorized imaging of visualimage projected on a screen, the imaging prevention method comprising:intermittently emitting infrared light from a plurality of infraredlight projector means in relay pattern in accordance with apredetermined code information, whereby enabling information along atime axis direction to be recorded in imaging means of a personconducting the unauthorized act.
 12. A imaging prevention method forinterfering unauthorized imaging of visual image projected on a screen,the imaging prevention method comprising: intermittently emittinginfrared light from a plurality of infrared light projector means inrelay pattern in accordance with a predetermined code information,whereby enabling a two-dimensional information to be recorded in imagingmeans of a person conducting the unauthorized act.
 13. A imagingprevention method for interfering unauthorized imaging of visual imageprojected on a screen, the imaging prevention method comprising:controlling a plurality of infrared light projector means to emit in apredetermined combination, whereby enabling a two-dimensionalinformation to be recorded in imaging means of a person conducting theunauthorized act.
 14. A imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: disposing at least one or more infraredlight projector means at a rear side of the screen viewing from aviewer/audience side, said at least one or more infrared light projectormeans comprising an array of light emitting devices, and controllingindividual light emitting device to generate an emission pattern of saidinfrared light, whereby enabling a predetermined information to berecorded in imaging means of a person conducting the unauthorized act.15. A imaging prevention method for interfering unauthorized imaging ofvisual image projected on a screen, the imaging prevention methodcomprising: detecting brightness at a screen surface with at least oneor more light sensors facing said screen surface, and increasing anamount of infrared light projected from an infrared light projectormeans as the detected brightness of said screen surface decrease, saidat least one or more light sensors being disposed behind said screenviewing from viewer/audience side.
 16. A imaging prevention method forinterfering unauthorized imaging of visual image projected on a screen,the imaging prevention method comprising: detecting brightness at ascreen surface with at least one or more light sensors facing saidscreen surface, and projecting infrared light from at least one or moreinfrared light projector means in case that the brightness of saidscreen surface is equal or less than a predetermined brightness, wherebyenabling said infrared light to be incident into imaging means of aperson conducting the unauthorized act, said at least one or more lightsensors being disposed behind said screen viewing from viewer/audienceside.
 17. The imaging prevention method according to claim 16, furthercomprising: projecting infrared light when a predetermined number ofdetection results are obtained, wherein each of said detection resultsindicates that the brightness of said screen surface is equal or lessthan said predetermined brightness, and each of said detection resultsis obtained from one of said light sensor disposed in a vicinity of thecenter of said screen.
 18. A imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: detecting brightness at a screen surfacewith at least one or more light sensors facing said screen surface, andindividually projecting infrared light from at least one or moreinfrared light projector means in case that the brightness of saidscreen surface is equal or less than a predetermined brightness, wherebyenabling said infrared light to be incident into imaging means of aperson conducting the unauthorized act, said at least one or more lightsensors being disposed behind said screen viewing from viewer/audienceside, and said infrared light projector means projecting the infraredlight being associated with an area corresponding to the light sensordetecting the brightness equal or less than said predeterminedbrightness.
 19. A imaging prevention method for interfering unauthorizedimaging of visual image projected on a screen, the imaging preventionmethod comprising: reproducing time information, in which brightness atthe screen becomes equal or less than a predetermined brightness value,from a recording medium, and projecting infrared light from at least oneor more infrared light projector means in accordance with the reproducedinformation, whereby enabling said infrared light to be incident intoimaging means of a person conducting the unauthorized act.
 20. A imagingprevention method for interfering unauthorized imaging of visual imageprojected on a screen, the imaging prevention method comprising:reproducing area and time information, in which brightness at the screenbecomes equal or less than a predetermined brightness value, from arecoding medium, and individually projecting infrared light from atleast one or more infrared light projector means associated withcorresponding area on the screen in accordance with the reproducedinformation, whereby enabling said infrared light to be incident intoimaging means of a person conducting the unauthorized act.
 21. A imagingprevention method for interfering unauthorized imaging of visual imageprojected on a screen, the imaging prevention method comprising:receiving information from a network for time in which brightness at thescreen becomes equal or less than a predetermined brightness value insynchronization with the projection of said visual image, and projectinginfrared light from at least one or more infrared light projector meansin accordance with the received information, whereby enabling saidinfrared light to be incident into imaging means of a person conductingthe unauthorized act.
 22. A imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: receiving information from a network forarea and time in which brightness at the screen becomes equal or lessthan a predetermined brightness value in synchronization with theprojection of said visual image, and individually projecting infraredlight from at least one or more infrared light projector meansassociated with corresponding areas on the screen in accordance with thereceived information, whereby enabling said infrared light to beincident into imaging means of a person conducting the unauthorized act.23. A imaging prevention method for interfering unauthorized imaging ofvisual image projected on a screen, the imaging prevention methodcomprising: projecting infrared light from at least one or more infraredlight projector means during a period of shielding the projection lightwith a frame transferring shutter when the visual image is projectedfrom a film type projector means, whereby enabling said infrared lightto be incident into imaging means of a person conducting theunauthorized act.
 24. A imaging prevention method for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention method comprising: projecting infrared light from at leastone or more infrared light projector means disposed in a vicinity of thescreen, whereby enabling said infrared light reflected on the screen tobe incident into imaging means of a person conducting the unauthorizedact.
 25. A imaging prevention method for interfering unauthorizedimaging of visual image projected on a screen, the imaging preventionmethod comprising: automatically adjusting a projection direction of atleast one or more infrared light projector means in correspondence withsize change of the screen, said at least one or more infrared lightprojector means being disposed in a vicinity of the screen, andprojecting infrared light to the adjusted projection direction, wherebyenabling said infrared light reflected on the screen to be incident intoimaging means of a person conducting the unauthorized act.
 26. A imagingprevention system for interfering unauthorized imaging of visual imageprojected on a screen, the imaging prevention system comprising: atleast one or more infrared light projector means disposed at a rear sideof the screen viewing from a viewer/audience side for projectinginfrared light so as said infrared light to be incident into imagingmeans of a person conducting the unauthorized act.
 27. The imagingprevention system according to claim 26, wherein: said infrared lightprojector means is disposed in such a way that at least a part of saidinfrared light is directly incident into said imaging means of a personconducting the unauthorized act without transmitting through the screen.28. The imaging prevention system according to claim 26, wherein: saidinfrared light projector means is disposed in such a way that at least apart of said infrared light transmits through the screen and is incidentinto said imaging means of a person conducting the unauthorized act. 29.The imaging prevention system according to claim 26, wherein: saidinfrared light projector means is disposed in such a way that at least apart of said infrared light directly is incident into said imaging meansof a person conducting the unauthorized act via passing through apass-through part provided in the screen.
 30. A imaging preventionsystem for interfering unauthorized imaging of visual image projected ona screen, the imaging prevention system comprising: at least one or moreinfrared light projector means disposed at a front side of the screenviewing from a viewer/audience side for projecting infrared light so assaid infrared light directly to be incident into imaging means of aperson conducting the unauthorized act.
 31. A imaging prevention systemfor interfering unauthorized imaging of visual image projected on ascreen, the imaging prevention system comprising: at least one or moreinfrared light projector means disposed in a vicinity of the screen forprojecting infrared light so as said infrared light to be directlyincident into imaging means of a person conducting the unauthorized act.32. A imaging prevention system for interfering unauthorized imaging ofvisual image projected on a screen, the imaging prevention systemcomprising: at least one or more infrared light projector means forprojecting infrared light; and infrared light reflection means forreflecting infrared light projected from at least one or more infraredlight projector means so as said infrared light to be directly incidentinto imaging means of a person conducting the unauthorized act.
 33. Theimaging prevention system according to claim 32, further comprising:actuator means for variably controlling said infrared light reflectionmeans or its reflection surface so as that the reflection light fromsaid infrared light reflection means scans an area of theviewer/audience side.
 34. A imaging prevention system for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention system comprising: at least one or more infrared lightprojector means for projecting infrared light; and emission controlmeans for controlling said at least one or more infrared light projectormeans to emit intermittently so as imaging means of a person conductingthe unauthorized act record a predetermined pattern of the intermittentemission.
 35. A imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the imaging preventionsystem comprising: at least one or more infrared light projector meansfor projecting infrared light; and emission control means forcontrolling said at least one or more infrared light projector means toemit intermittently in accordance with a predetermined code informationso as imaging means of a person conducting the unauthorized act recordinformation along a time axis.
 36. A imaging prevention system forinterfering unauthorized imaging of visual image projected on a screen,the imaging prevention system comprising: at least one or more infraredlight projector means for projecting infrared light; and emissioncontrol means for controlling a plurality of infrared light projectormeans to emit intermittently in relay format in accordance with apredetermined code information so as imaging means of a personconducting the unauthorized act record information along a time axis.37. A imaging prevention system for interfering unauthorized imaging ofvisual image projected on a screen, the imaging prevention systemcomprising: at least one or more infrared light projector means forprojecting infrared light; and emission control means for controlling aplurality of infrared light projector means to emit intermittently inrelay format in accordance with a predetermined code information so asthat imaging means of a person conducting the unauthorized act record atwo-dimensional information.
 38. A imaging prevention system forinterfering unauthorized imaging of visual image projected on a screen,the imaging prevention system comprising: at least one or more infraredlight projector means for projecting infrared light; and emissioncontrol means for controlling a plurality of infrared light projectormeans to emit intermittently in a predetermined combination so as thatimaging means of a person conducting the unauthorized act record atwo-dimensional information.
 39. A imaging prevention system forinterfering unauthorized imaging of visual image projected on a screen,the imaging prevention system comprising: at least one or more infraredlight projector means comprising a plurality of light emitting devicesdisposed in an array for projecting infrared light; and an infraredlight projection control unit for individually controlling said lightemitting device of said infrared light projector means disposed in arear side of the screen viewing from a viewer/audience side so as thatimaging means of a person conducting the unauthorized act record apredetermined information corresponding to an emission pattern of saidinfrared light.
 40. A imaging prevention system for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention system comprising: at least one or more infrared lightprojector means for projecting infrared light; and at least one or morelight sensors disposed in a rear side of the screen viewing from aviewer/audience side for detecting brightness of the facing screen,wherein a detection result of said light sensor is outputted to thecorresponding infrared light projector means as a light amount adjustingsignal for increasing an amount of the infrared light as the detectedbrightness of the screen surface decrease.
 41. A imaging preventionsystem for interfering unauthorized imaging of visual image projected ona screen, the imaging prevention system comprising: at least one or moreinfrared light projector means for projecting infrared light; at leastone or more light sensors disposed in a rear side of the screen viewingfrom a viewer/audience side; and an infrared light projection controlunit for accepting output signals from said light sensors and forcontrolling said at least one or more infrared light projector means toproject the infrared light in case that a brightness of the screensurface facing said light sensor is equal or less than a predeterminedbrightness.
 42. The imaging prevention system according to claim 41,wherein said an infrared light projection control unit control toproject infrared light when a predetermined number of detection resultsare obtained, wherein: each of said detection results indicates that thebrightness of said screen surface is equal or less than saidpredetermined brightness, and each of said detection results is obtainedfrom one of said light sensor disposed in a vicinity of the center ofsaid screen.
 43. A imaging prevention system for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention system comprising: at least one or more infrared lightprojector means for projecting infrared light; at least one or morelight sensors disposed in a rear side of the screen viewing from aviewer/audience side; and an infrared light projection control unit foraccepting output signals from said light sensors and for controllingindividually to project infrared light from said at least one or moreinfrared light projector means in case that a brightness of the screensurface is equal or less than a predetermined brightness; wherein saidat least one or more infrared light projector means projecting theinfrared light being associated with an area corresponding to the lightsensor detecting the brightness equal or less than said predeterminedbrightness.
 44. A imaging prevention system for interfering unauthorizedimaging of visual image projected on a screen, the imaging preventionsystem comprising: at least one or more infrared light projector meansfor projecting infrared light; reproducing means for reproducing timeinformation, in which brightness at the screen becomes equal or lessthan a predetermined brightness value, from a recording medium; and aninfrared light projection control unit for controlling projection ofinfrared light from said at least one or more infrared light projectormeans in accordance with the reproduced information.
 45. A imagingprevention system for interfering unauthorized imaging of visual imageprojected on a screen, the imaging prevention system comprising: atleast one or more infrared light projector means for projecting infraredlight; reproducing means for reproducing area and time information, inwhich brightness at the screen becomes equal or less than apredetermined brightness value, from a recording medium; and an infraredlight projection control unit for controlling individually projection ofinfrared light from said at least one or more infrared light projectormeans associated with corresponding areas on the screen in accordancewith the reproduced information.
 46. A imaging prevention system forinterfering unauthorized imaging of visual image projected on a screen,the imaging prevention system comprising: at least one or more infraredlight projector means for projecting infrared light; receiving means forreceiving information from a network for time in which brightness at thescreen becomes equal or less than a predetermined brightness value insynchronization with the projection of said visual image; and aninfrared light projection control unit for controlling projection ofinfrared light from said at least one or more infrared light projectormeans in accordance with the received information.
 47. A imagingprevention system for interfering unauthorized imaging of visual imageprojected on a screen, the imaging prevention system comprising: atleast one or more infrared light projector means for projecting infraredlight; receiving means for receiving information from a network for areaand time in which brightness at the screen becomes equal or less than apredetermined brightness value in synchronization with the projection ofsaid visual image, and an infrared light projection control unit forindividually controlling projection of infrared light from said at leastone or more infrared light projector means associated with correspondingareas on the screen in accordance with the received information.
 48. Aimaging prevention system for interfering unauthorized imaging of visualimage projected on a screen, the imaging prevention system comprising:at least one or more infrared light projector means comprising aplurality of light emitting device disposed in an array form forprojecting infrared light; shielding period detection means fordetecting a period of shielding the projection light with a frametransferring shutter when the visual image is projected from a film typeprojector means; and an infrared light projection control unit forcontrolling emission of said infrared light projector means based ondetection results of said shielding period detection means.
 49. Aimaging prevention system for interfering unauthorized imaging of visualimage projected on a screen, the imaging prevention system comprising:at least one or more infrared light projector means disposed in avicinity of the screen surface at a front side of the screen viewingfrom a viewer/audience so as said infrared light reflected on the screento be incident into imaging means of a person conducting theunauthorized act.
 50. A imaging prevention system for interferingunauthorized imaging of visual image projected on a screen, the imagingprevention system comprising: at least one or more infrared lightprojector means disposed in a vicinity of the screen surface forprojecting infrared light to the screen; projecting direction actuatormeans for driving said infrared light projector means to vary itsprojection direction; memory means for recording projecting directioninformation of each infrared light projector means according to a screensize; and projecting direction control means for reading out saidprojecting direction information from said memory means when aninstruction to change the screen size is detected, for providing theread-out information to said projecting direction actuator means, andfor automatically adjusting a projecting direction of said infraredlight projector means.
 51. Apparatus for interfering unauthorizedimaging of visual image appeared on a screen, comprising: an infraredlight projector disposed near said screen for projecting infrared lightin such a way that the infrared light can be incident onto imagingapparatus that is being operated for imaging the visual image on saidscreen.
 52. Apparatus for interfering unauthorized imaging of visualimage appeared on a screen, comprising: an infrared light projectorprojecting infrared light; and infrared light reflector reflectinginfrared light projected from said infrared light projector so as saidinfrared light to be incident onto imaging means that is being operatedfor imaging the visual image on said screen.
 53. Apparatus forinterfering unauthorized imaging of visual image appeared on a screen,comprising: an infrared light projector projecting infrared light; andemission controller controlling emission of said infrared lightprojector in accordance with a predetermined emission pattern. 54.Apparatus for interfering unauthorized imaging of visual image appearedon a screen, comprising: an infrared light projector comprising aplurality of light emitting devices disposed in an array format forprojecting infrared light; and a control unit controlling said lightemitting devices.
 55. Apparatus for interfering unauthorized imaging ofvisual image projected on a screen, comprising: an infrared lightprojector projecting infrared light; a light sensor detecting brightnessof said screen; and a control unit controlling said infrared lightprojector in accordance with a detection result of said light sensor.